Synthesis of stable zinc-phosphate micro/nanoparticles under acid and alkaline conditions

Synthesis of stable zinc-phosphate micro/nanoparticles under acid and alkaline conditions | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Synthesis of stable zinc-phosphate micro/nanoparticles under acid and alkaline conditions Benjamín Valdez-Salas, Karen Guillén-Carvajal, Ernesto Beltrán-Partida, and 3 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6908597/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract In the present work, we synthesize zinc-phosphate particles (Zn 3 (PO 4 ) 2 ) of micro and nanometric sizes (ZnPMCPs y ZnPNPs) through chemical reduction in acidic and alkaline conditions in order to obtain stable colloidal solutions through resuspension of the particles. In acidic media, the addition of hydrochloric acid (HCl), citric acid (AC), or ascorbic acid (AA) created spheric structures with a zeta potential superior to +100 mV. On the other hand, the addition of ammonium hydroxide (NH 4 OH) created oval flat-shaped structures with zeta potential lower than -53.9 mV thus showing an agglomeration tendency in alkaline media. Therefore, these findings indicate that HCl was the most effective media for resuspension, which allowed the obtention of nanoparticles with an average size smaller than 25 nm and highly stable, which makes this an easy and reproducible method. The results from this study present a new strategy for the obtention of micro/nanoparticles with high colloidal stability, which can be recovered from previous resuspension processes without losing their stability and have potential applications in the design of biomedical and anticorrosive coatings. Oval-layer structure pH-controlled synthesis micro/nano spheres ultrasonication dependent structure Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 1. Introduction Inorganic microparticles (MCPs) and nanoparticles (NPs) are materials composed of metallic and ceramic elements. These types of compounds exhibit good biocompatibility, hydrophilicity, non-toxicity, stability, electrical, and optical properties, with respect to their counterparts without controlled physicochemical modifications [ 1 ], [ 2 ]. Among the wide variety of MCPs and inorganic NPs, \(\:Z{n}_{3}({{PO}_{4})}_{2}\) presents interesting properties as serve as an effective anticorrosive coating [ 3 ]-[ 7 ], as an additive in paints [ 8 ], [ 9 ], as well as in controlled drug delivery systems [ 10 ], [ 11 ]. However, it is important to highlight that these materials, both in bulk and nanostructured configurations, are collected and used in powder form since it is not soluble at pH above 7.16 [ 12 ]. The precipitation of this white powder serves as a clear indicator of the formation and poor stability of the material. One of the most common methods for solubilizing phosphate materials is by using microorganisms that can perform various routes of action, such as the production of a siderophore, utilizing the phytase enzyme, or generating acids and H + ions [ 13 ]-[ 15 ]. In the case of the latter mentioned method, the phosphate is converted into a soluble form, like the case of phosphoric acid, \(\:{H}_{3}{PO}_{4};\) where the metal is coupled to the acid or remains in divalent or trivalent form; in contrast, the phosphate remains in orthophosphate form [ 13 ]. Thus, when \(\:Z{n}_{3}({{PO}_{4})}_{2}\) is in contact with the acid media, a primary product is formed between these two compounds. The subsequent chain of additional reactions leading to a decay in solubility and the final formation of amorphous zinc orthophosphate has a very low solubility in water. [ 13 ], [ 16 ], [ 17 ]. Therefore, in the present work, we design the synthesis of \(\:Z{n}_{3}({{PO}_{4})}_{2}\) (ZnP) micro and nanoparticles by varying the pH, we aimed to analyze their stability in aqueous media. For this purpose, we applied three acidic media; citric acid (CA), hydrochloric acid (HCl) and ascorbic acid (AA); and a basic medium of ammonium hydroxide, as along with different surfactant concentrations. This synthetic strategy presents a promising route for the controlled formation of ceramic micro/nanoparticles with significant implications for stability in relation to pH and synthesis medium. 2. Materials and methods 2.1 Materials The zinc chloride ( \(\:Zn{Cl}_{2}\) ), and monopotassium phosphate ( \(\:K{H}_{2}{PO}_{4})\) were purchased from FAGALab, Mexico; the ascorbic acid (AA) from Fisher, Mexico; hydrochloric acid ( \(\:HCl)\) and ammonium hydroxide (N \(\:{H}_{4}OH)\) from Baker, Mexico; Cocobetaine (CC) from Chemie NRW, Mexico; and citric acid (AC) from Fermont, Mexico. 2.2 Method 2.2.1 Synthesis of ZnPNPs by chemical method The experimental zinc phosphate micro- and nanoparticles (ZnPMCNPs and ZnPNPs) were synthesized by chemical method in acidic and a separate alkaline medium using a surfactant to stabilize at concentrations of 0.1%, 0.5% and 1% (w/v). Initially, 2.5 mL of the surfactant solution were placed in a glass vessel and ultrasonicated for 5 min using an ultrasonic bath (BRANSON) at a 22 kHz frequency and an amplitude of 40%. Then, in three separate vessels we added 5 mL of a 0.05 M \(\:Zn{Cl}_{2}\) aqueous solution and one of the three acidic media (HCl 10% (w/w), AC 10% (w/w) and AA 10% (w/w)) until obtaining a pH of 4. Then, the solution was mixed for 10 min and subsequently 5 mL of a 0.025 M \(\:K{H}_{2}{PO}_{4}\) solution was added dropwise and left to react for 10 min. The final pH of the solution was adjusted to pH 4.2 with the previously mentioned acidic solutions or to pH 8.5 with 10% N \(\:{H}_{4}OH\) and allowed to react for 10 min. Finally, the resulting mixture was ultrasonicated for 10 min using an OMNI SONIC RUPTOR 400 unit with 22 kHz frequency and 40% amplitude. For the alkaline samples, the precipitate was collected and washed three times with ethanol 70% w/w at 6,000 RPM for 10 min. After the last wash, the samples were dried in a desiccator for 48h at room temperature and resuspended. A schematic illustration of the procedure is described in Fig. 1 and in Table S1 are shown the corresponding labels. 2.2.2 Resuspension of NPs The resuspension of MCPs and NPs was carried out by modifying the pH of the solution (up to 4.2) with the modified ZnPMCNPs and ZnPNPs, which were synthesized by using the following solutions: HCl 10% (w/w), AC 10% (w/w) and AA 10% (w/w). 2.3 Nanoparticle characterization The morphology, homogeneity and size of the synthesized MCPs and NPs were evaluated using Field Emission Scanning Electron Microscopy (FE-SEM; LYRA 3, Tescan, Brno, Czech Republic) with an accelerating voltage of 10 kV. The chemical composition was analyzed by energy dispersive X-ray spectroscopy (EDX, Bruker, Xflash 6I30, Billerica, MA, USA) coupled to FE-SEM. Prior to analysis the MCPs and NPs were taken directly from the resuspension solution with 10% HCl and placed on a double-sided adhesive carbon conductive tape and dried at room temperature. To evaluate the size distribution (hydrodynamic diameter) and zeta potential ( \(\:\zeta\:\) ) of MCPs and NPs, dynamic light scattering (DLS; Nanotrac Wave II system Microtrac, North Wales, PA, USA) was used. The resuspended solutions from the different acidic medium used (HCl 10% (w/w), AC 10% (w/w) y AA 10% (w/w)) at pH 4. 2 were previously sonicated in an ultrasonic bath (DK300PF, China) at room temperature, 120 W for 10 min, and then filtered (Whatman, No. 4). Then, the DLS were caried out using a delay time of 30 s and a run time of 30 s at room temperature [ 18 ]. 3. Results and Discussion 3.1 Morphology and growth mechanism analysis of micro/nano ZnP structures Recent works suggest that ZnPCMPs and ZnPNPs can be easily obtained through chemical methods using precursors such as zinc nitrate, dibasic sodium phosphate, dehydrogenated ammonium phosphate, zinc acetate, and ammonium phosphate. Moreover, other physicochemical parameters are applied, such as ultrasonication, high temperature, or varying the pH of the solution, commonly with a tendency to alkalinity [ 12 ], [ 16 ], [ 19 ]-[ 22 ]. These methods allow obtaining MCPs and NPs by precipitation with shapes including pyramidal hexagons, sheets, nanoflowers and hollow spheres. However, the synthesis and stabilization of these materials in the same reaction medium have not been achieved yet. In order to corroborate the formation of the MCPs and NPs before their resuspension and/or solubility increase; two samples of ZnP were meticulously analyzed by SEM-EDS under the same synthesis procedure with an initial pH of 4, and final alkaline (pH 8.5) or acidic pH (pH 4.2). The micrographs in Fig. 2 show that completely different microstructures can be obtained, depending on the pH of the reaction medium, achieving an orthorhombic system formed at pH 4.2 and a spherical morphology. On the other hand, a monoclinic system was obtained at pH 8.5 with the formation of flat ovals larger than spherical particles, which agrees with previous reports in the literature [ 21 ], [ 23 ]. According to these analyses, we can particularly attribute the increase in pH to the changes in Zn crystal orientation preference, crystal surface lattice density, and degree of dispersion observed [ 21 ]. Thus, providing a reliable understanding of the role of the pH reaction medium in determining microstructure formation and crystal orientation. To explain the effect of pH on the morphological change shown, HCl (10% w/w) and NH 4 OH (10% w/w) solutions were considered as pH adjusting solutions according to the following reaction scheme: In solution \(\:\:K{H}_{2}P{O}_{4}\:\) can ionize into \(\:{P{O}_{4}}^{3-}\) , a process by which an acid, base, or a salt dissociates into ions in an aqueous solution. In the case of \(\:K{H}_{2}P{O}_{4}\) , this compound ionizes in three stages (successive protonation of the phosphate ion) according to reactions (1) to (3). Hydrolysis is the reaction of the study ion with water, generating OH − (in basic media) or H 3 O + (in acidic media). The preference between the two pathways depends on the acidity constant ( \(\:{K}_{a})\) and the hydrolysis constant ( \(\:{K}_{h}\) ). In the case of \(\:{HP{O}_{4}}^{2-}\:\) it has a preference to ionize over hydrolyze (4) according to their constants ( \(\:{K}_{a3}<{K}_{h})\) [ 24 ]. \(\:K{H}_{2}P{O}_{4}\leftrightharpoons\:{K}^{+}+{{H}_{2}P{O}_{4}}^{-}\) \(\:{K}_{a1}=7.5x{10}^{-3}\) (1) \(\:{{H}_{2}P{O}_{4}}^{-}\leftrightharpoons\:{H}^{+}+{HP{O}_{4}}^{2-}\) \(\:{K}_{a2}=6.2x{10}^{-8}\) (2) \(\:{HP{O}_{4}}^{2-}\leftrightharpoons\:{H}^{+}+{P{O}_{4}}^{3-}\) \(\:{K}_{a3}=2.2x{10}^{-13}\) (3) \(\:{HP{O}_{4}}^{2-}+{H}_{2}O\leftrightharpoons\:{{H}_{2}P{O}_{4}}^{-}+\:{OH}^{-}\) \(\:{K}_{h}=1.6x{10}^{-7}\) (4) \(\:{{H}_{2}P{O}_{4}}^{-}+{H}_{2}O\leftrightharpoons\:{H}_{3}P{O}_{4}+\:{OH}^{-}\) \(\:{K}_{h}=1.3x{10}^{-12}\) (5) \(\:{P{O}_{4}}^{3-}+{H}_{2}O\leftrightharpoons\:{HP{O}_{4}}^{2-}+{OH}^{-}\:\) (6) When the medium is acidic (pH < 7), there is a preference for \(\:{{H}_{2}P{O}_{4}}^{-}\) to hydrolyze over ionize according to reactions (2), (4) and (5) facilitating the stability of \(\:{{H}_{2}P{O}_{4}}^{-}\:\) because of \(\:{H}^{+}\:\) ions, carrying out the reaction (7). In addition, the concentration of \(\:{P{O}_{4}}^{3-}\) anions are reduced due to the equilibrium in the hydrolytic reaction (6) which is directed in the right-hand direction of the reaction, where these \(\:{P{O}_{4}}^{3-}\) ions prefer to react with \(\:{Zn}^{2+}\) ions to form ZnP (8): $$\:3{Zn}^{2+}+{{6H}_{2}P{O}_{4}}^{-}\to\:3Zn{\left({H}_{2}P{O}_{4}\right)}_{2}\to\:{Zn}_{3}{\left(P{O}_{4}\right)}_{2}+4{H}_{3}P{O}_{4}$$ 7 $$\:3{Zn}^{2+}+{2P{O}_{4}}^{-3}\to\:{Zn}_{3}{\left(P{O}_{4}\right)}_{2}$$ 8 As a relatively high concentration of free H + and H 3 O + ions is present in contact with the ZnP, strong hydrogen bonds are formed between the contact surfaces of the Zn 3 (PO 4 ) 2 and H 2 O nuclei, generating an increased repulsion between them. Therefore, the resulting growth anisotropy along certain crystal planes formed nano and microbumps, with relatively small, uniform particles showing a low degree of orientation, which in our case resulted in spherical NPs and MCPs, illustrating an orthorhombic crystal system configuration [ 20 ]. When the medium is alkaline (pH > 7), the \(\:{HP{O}_{4}}^{2-}\) anion remains stable due to the presence of \(\:{OH}^{-}\) carrying out the reaction (9): $$\:3{Zn}^{2+}+{2HP{O}_{4}}^{2-}+2{OH}^{-}\to\:{Zn}_{3}{\left(P{O}_{4}\right)}_{2}+2{H}_{2}O$$ 9 If the pH value > 8 to 8.5, the concentration of \(\:{OH}^{-}\:\) is slightly higher than \(\:{H}^{+}\) ions in the reaction medium; thus, the concentration of \(\:{P{O}_{4}}^{3-}\) anions increase due to the leftward lean of the hydrolytic reaction equilibrium (6). Thus, one can have not only the reaction between \(\:{P{O}_{4}}^{3-}\) and \(\:{Zn}^{2+}\) but also with \(\:{N{H}_{4}}^{+}\) cations due to the pH adjustment from \(\:N{H}_{4}OH\) , thus forming zinc ammonium phosphate ( \(\:N{H}_{4}ZnP{O}_{4}\) ). Nonetheless, since our initial reaction medium was acidic, there was a larger amount of \(\:{H}^{+}\) ions available, thus not allowing the formation of \(\:N{H}_{4}ZnP{O}_{4}\) , as shown in the EDS analysis, which only contemplates the presence of Zn, P, O and a trace of C (Figure S1 ). In this sense, it is important to highlight that by applying this synthetic strategy we can obtain ZnP micro and nanoparticles with improved physicochemical control without requiring the purification of the reaction medium to eliminate the \(\:N{H}_{4}ZnP{O}_{4}\) . On the other hand, the MCNPs and NPs in the alkaline medium synthesized in this work presented a homogeneous and stable final structure. Micro/nanosheets were generated that assembled radially from the center outwards, increasing in width with the integration of multiple layers, following a crystal growth orientation that generated an oval-flat monoclinic shape [ 20 ]. This is due to the change in the traditional synthesis methods in the alkaline medium where they give rise to the characteristic spikes, sheets or microflowers [ 16 ], [ 19 ], [ 21 ] attributed to the complex equilibrium between the ions in the reaction system and the adsorption of ions on the different faces of the crystal. The formation of sheets is mainly influenced by \(\:{HP{O}_{4}}^{2-}\) ions, and not by \(\:{{H}_{2}P{O}_{4}}^{-}\) , as observed in our reaction, due to a lower concentration of free \(\:{H}^{+}\) with a lower repulsion between the crystal surfaces generating a higher agglomeration [ 12 ], [ 21 ]. Therefore, an increase in the pH of the reaction system affects the stability of the ions due to the equilibrium between ionization and hydrolysis, resulting mainly in small self-assembling lamellar crystals along one direction of the crystalline plane. It is important to highlight that we obtained smaller particles sizes than those reported in the literature, even at similar final pH conditions as shown in Table 1 . Table 1 Size of ZnPCMPs and ZnPNPs according to different works pH médium Length ( \(\:\mu\:m)\) Width ( \(\:\mu\:m)\) Thickness ( \(\:\mu\:m)\) Size ( \(\:\mu\:m)\) Structure Reference 2.6 - - - 1.5–1.8 Microsheet [ 21 ] 3 ~ 10.6 ~ 6.1 0.050–0.1 - Nanosheet [ 19 ] 3 - - 0.1–1.8 - Microsheet [ 21 ] 3.5 0.9–1.5 0.6 - - Orthorhombic [ 20 ] 4 ~ 20.3 ~ 10.4 ~ 0.2–0.5 - Microplates [ 19 ] 4 0.3–2.5 0.2–1.5 - - Microflower [ 21 ] 4 - - - ~ 7 Microflower [ 20 ] 5 - - - 9.8 Microflower [ 21 ] 5 0.2–0.8 - - - Microsheet [ 25 ] 5 2 - - - Microsheet [ 25 ] 6 - - ~ 0.05 ~ 6 Microsphere [ 19 ] 6 - - - 11 Microflower [ 21 ] 6 ~ 4 ~ 3 ~ 0.08 - Nanosheet [ 20 ] 6.5–7 - - - - Microflower [ 20 ] 7 - - - ~ 10.1 Mixture (flower, bipyramid, prism) [ 21 ] 7 - - - 0.0036–0.04 Nanosphere [ 11 ] 7 - - - ~ 3.8 Microflower [ 11 ] > 7.2 - - - 1.43 Hexagonal bipyramid [ 12 ] > 7.2 - - - 1.5 Platelike [ 12 ] 8 8.8 - 0.04–0.9 - Flower [ 21 ] 8 - - - 10–12 Mixture (orthorhombic, monoclinic and dandelion) [ 20 ] 8.5 0.2–0.5 6 - - Multilayer nanosheet [ 20 ] 9 - - - 9 Microflower [ 21 ] 9 - - - (1.3 x 1 x 0.5) Microcube [ 20 ] 10 - - - - Microflower [ 21 ] 11 - - - 2–8 Microflower [ 21 ] 11 - - - - Irregular NPs [ 20 ] Alkali - - - 0.2–0.5 Amorphous [ 26 ] 4.2 - - - 0.06–0.3 Sphere This work 8.2 1.65 - 0.12–0.14 - Oval-flat This work According to Zhou et al and Yue et al [ 20 ], [ 21 ], particles obtained in acidic media (pH < 3), have a higher degree of orientation that enables the formation of complete and long lamellar crystals. Meanwhile, at pH 4 relatively small and almost uniform particles with low degree of orientation can be obtained. In contrast, at pH levels from 5 to 6 flower structures with sizes between 9.8 to 11 µm are formed, for p. However, the sizes detected are around 8.8 and 9 µm in pH 8 and 9, where in the latter the multiple layers in each of the petals can be observed. Likewise, for \(\:N{H}_{4}ZnP{O}_{4}\) , sheet structures can be obtained at pH 8.5 and cube structures at pH 9. Finally, at pH 10 and 11, the product obtained demonstrates a structure of nanowires and sheets/nanospikes differ from each other or are spherical when it comes to \(\:N{H}_{4}ZnP{O}_{4}\) . Figure 3 shows a scheme illustrating the previously mentioned information. Based on our results, we suggest that the pH value is possibly the most important factor in controlling the reaction course undergone by ZnP micro/nanparticulate materials, as a modulator of the size and the structural morphology. Likewise, it has been mentioned that the sonicating process increases the nucleation rate, which causes an increase in crystallization, and therefore, in crystal growth when synthesizing ZnPMCPs and ZnPNPs [ 27 ] being this agglomeration much lower when resuspension is performed [ 28 ]. For this reason, the sheets usually have measurements that are no longer considered nanometric. In our process we performed the two previous points, so we obtained better oval sheets and then in the resuspension process these had smaller sizes, allowing us to describe a synthetic strategy for the control in the micro/nanostructured size. 3.2 Synthesis mechanism A schematic diagram of the formation of the spherical and flat oval structures of ZnP in acidic and alkaline media, respectively, is shown in Fig. 4 . The aqueous surfactant solution (CC), upon exposure to ultrasonic irradiation initiates self-aggregation to form spherical micelle structures. Since the CC contains an amphoteric surfactant, it can attract Zn + 2 ions to the surface of the micelles. These adsorbed micelles of zinc ions provide nucleation domains for the subsequent reaction between Zn + 2 and PO 4 3− ions [ 5 , 6 ]. Additionally, heating caused by ultrasonic vibration can facilitate the generation of crystalline nuclei, resulting in a uniformly distributed accumulation in solution. Producing uniform crystalline grains with growth in all directions equally, following the shape of the micelle formed by the surfactant [ 10 ], [ 22 ]. Based on Oswald ripening, which is a thermodynamic phenomenon that results in the growth of large droplets through the coalescence of smaller droplets [ 29 ], the larger ZnP grains grow, while the smaller grains continue to dissolve, thus producing uniform particle sizes in the ZnP crystals. Under acidic conditions, the concentration of free \(\:{H}^{+}\) ions formed strong hydrogen bonds between the contact surfaces of ZnP nuclei and water, generating strong repulsion between these nuclei. In this way, growth in some planes with respect to another is prohibited, leading to the formation of microbumps [ 20 ], [ 21 ], [ 30 ]. Similarly, as demonstrated in this study, with an increase in the pH of the reaction system, the stability of the ions is affected, forming small oval-shaped crystals, probably attributed to the controlled concentrations of \(\:{HP{O}_{4}}^{2-}\) and \(\:{{H}_{2}P{O}_{4}}^{-}\) at different pH. Since the small sheet-like crystals have a large specific surface area and the corresponding surface tension had a reduced driving force, then the small particles accumulated spontaneously, demonstrating significant self-assembly ability [ 21 ], [ 30 ], [ 31 ]. 3.3 DLS and resuspension The ZnPCMPs generated the characteristic precipitate of the bioceramic materials by the formation of the compounds \(\:{Zn}_{3}{\left({PO}_{4}\right)}_{2}\) in an alkaline medium, except for the ZnMCPs and ZnPNPs which were synthesized in an acidic medium. To analyze the particle and \(\:\zeta\:\) sizes of each synthesis, resuspension was performed according to Tables S2 and S3. Thus, the most satisfactory results in terms of resuspension and yield were obtained when an acidic medium was used, especially with the 10% HCl solution. According to the results (Table S4), using the AC solution as the resuspension medium, it is evident that the lower the amount of surfactant, the enhanced the tendency for the formation of CMPs and NPs. In contrast, using the AA solution a greater amount of surfactant is necessary, and in turn a greater amount of acid is needed to carry out the resuspension, which is in correspondence with an increase in the size of ZnP. Therefore, this behavior explains that the presence of NPs was reduced by the strong ionization of \(\:{Zn}_{3}{\left({PO}_{4}\right)}_{2}\) in Zn 2+ and PO 4 − 3 but with little nucleation. On the other hand, according to the particle size distribution, and the potential \(\:\zeta\:\) (Table 2 , Fig. 5 and Figure S1 ), it is not convenient to resuspend with AA solution since, although it is a good reductant, when using an excess amount needed in the resuspension, it tends to form clusters and increase the particle size. Thus showing a low potential value characteristic of an unstable colloidal solution (+ 4.6 mV for the AA solution using 0.5% CC (2AA) and − 9.1 mV for the alkaline solution of resuspended with AA using 1% CC (1BAA)). In the case of the AC solution using 0.1% CC (3AC) and the alkaline solution resuspended with AC using 1% CC (1BAC), two important peaks were obtained, one with a higher concentration of MCPs at sizes smaller than 300 nm and the other larger than 7 µm. On the other hand, the alkaline solution resuspended with AC using 0.1% CC (3BAC) obtained MCPs with a mean diameter of 322 nm. Therefore, when the concentration of the surfactant CC is 1% in the presence of AC, a dispersed size distribution is obtained, while at 0.1%, it presents a mostly homogeneous distribution. The higher the surfactant concentration with the use of a weak acid such as AC, the size of the nanostructure increases due to greater agglomeration, which results in different size distributions. On the other hand, a lower surfactant concentration in the presence of a weak acid allows the acid to act on the double layer and generate a greater stabilization without agglomeration [ 25 ], [ 33 ], [ 34 ]. Table 2 Characteristic values of each resuspended solution by DLS. A = acid, B = Alkaline, HCl = hydrochloric acid, citric acid = AC, ascorbic acid = AA, and CC = Cocobetaine Solución Acrónimo Potencial Z (mV) Media (nm) Solución A con AC utilizando 0.1% de CC 3AC + 118.4 193.4 Solución A con HCl utilizando 1% de CC 1HCl + 111.9 21.55 Solución A con AA utilizando 1% de CC 1AA + 200 1976 Solución A con AA utilizando 0.5% de CC 2AA + 4.6 448 / 1179 Solución B con AC utilizando 1% de CC 1BAC -200 20.37 Solución B con AC utilizando 0.1% de CC 3BAC -200 322 Solución B con HCl utilizando 0.5% de CC 2BHCl -53.9 213.2 Likewise, samples 1HCl and 2BHCl (in HCl) only presented a distribution peak, of NPs smaller than 100 nm with \(\:\zeta\:\) of + 111.9 mV, and MCPs smaller than 250 nm with a \(\:\zeta\:\) of -53.9 mV, respectively. At higher CC concentration, smaller particle sizes are obtained with higher colloidal stability. In this case, a synergy between the surfactant and the strong acid is obtained, due to the amphoteric character, which significantly improves their stability. It is proposed that the mechanism of reduction and stabilization occurs by the initial capping by the surfactant. Then the decrease in the size of the NPs is carried out by breaking the agglomerated groups that have generated. Thus, allowing to achieve a balance in the double layer that allows the electrostatic repulsion between them without agglomerating [ 33 ], [ 35 ]. It is generally appreciated that when MCPs and NPs are in acidic media, they tend to show positive zeta potential values, while in alkaline media they tend to show a negative value due to the amount of ions present in the solution of both H + and OH − , respectively [ 33 ], [ 36 ]. Considering the previous results derived from \(\:\zeta\:\) and the size distribution of the MCPs and NPs, a second run was made using the best-performing solution in an acid medium (1HCl) and in an alkaline medium (1BAC) to validate its replicability, as well as the effect on the improvement of the filtering method. The results are shown in Fig. 6 , where we can appreciate that there was an improvement in the arrangement and size of the NPs in 1HCl (9.31 nm). Meanwhile, in IBAC, the CMPs had larger sizes with a greater dispersion due to the appearance of more peaks, which could lead to lower stability. The volumetric mean in IBAC was 584 nm, with an area mean of 290.5 nm. Comparing with our MCPs in Fig. 2 , which is before resuspending, we can appreciate an improvement in size with no precipitate formation. These results indicated that the stability of the colloidal system is enhanced, suggesting improved resistance to precipitation and potentially leading to a longer shelf life. 4. Conclusion It was possible to synthesize and stabilize aqueous zinc phosphate micro- and nanoparticles solution in both acidic and alkaline media, obtaining initially similar structures and with variations in colloidal stability. In the case of acidic solution, nanospheres are obtained using HCl and AC at pH 4.2 and with a \(\:\zeta\:\) of + 111.9 mV and + 118.4 mV, respectively. In an alkaline medium, the best results were also obtained with resuspension using the AC and HCl solutions, resulting in spliced oval flake structures with micro- and nanometer thickness. The results of the present study provide a novel method for obtaining micro/nanoparticles with high colloidal stability, recoverable prior to resuspension processes, with potential applications in the design of biomedical and anticorrosion coatings. Declarations Supplementary information The online version contains supplementary material available at (doi of publication) Acknowledgments We thank to Instituto de Ingeniería of Universidad Autónoma de Baja California. Author Contributions Conceptualization, Benjamín Valdez-Salas, andKaren Guillén-Carvajal; methodology, Benjamín Valdez-Salas, and Karen Guillén-Carvajal; investigation, Benjamín Valdez-Salas, Karen Guillén-Carvajal, and Jorge Salvador-Carlos; software, Jorge Salvador-Carlos, and Mario Curiel-Alvarez resources, Benjamín Valdez-Salas,and Karen Guillén-Carvajal; writing—original draft preparation, Benjamín Valdez-Salas,Karen Guillén-Carvajal, and Ernesto Beltrán-Partida; writing—review and editing, Ernesto Beltrán-Partida, Nikola Nedev, and Mario Curiel-Alvarez; supervision, Benjamín Valdez-Salas,and Ernesto Beltrán-Partida; formal analysis, Karen Guillén-Carvajal, Jorge Salvador-Carlos, Nikola Nedev, and Ernesto Beltrán-Partida; visualization, Karen Guillén-Carvajal; validation, Benjamín Valdez-Salas,Karen Guillén-Carvajal, and Ernesto Beltrán-Partida; project administration, Karen Guillén-Carvajal. All authors have read and agreed to the final version of the manuscript. Funding No funds, grants, or other support was received. Data availability No datasets were generated or analyzed during the current study. Conflict of interest The authors declare no conflict of interest. The authors have no financial or proprietary interest in any material discussed in this article. Ethics approval and consent to participate Not applicable. Consent for publication All authors have read and agreed to the published version of the manuscript. Materials availability Not applicable. Code availability Not applicable. References W. Paul and C. P. Sharma, “Inorganic nanoparticles for targeted drug delivery,” in Biointegration of Medical Implant Materials , Elsevier, 2010, pp. 204–235. DOI: 10.1533/9781845699802.2.204 . Z. P. Xu, Q. H. Zeng, G. Q. Lu, and A. B. Yu, “Inorganic nanoparticles as carriers for efficient cellular delivery,” Chem Eng Sci , vol. 61, no. 3, pp. 1027–1040, Feb. 2006, DOI: 10.1016/j.ces.2005.06.019 . S. 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Valdez-Salas et al. , “Structure-activity relationship of diameter controlled Ag@Cu nanoparticles in broad-spectrum antibacterial mechanism,” Materials Science and Engineering: C , vol. 119, p. 111501, Feb. 2021, DOI: 10.1016/j.msec.2020.111501 . N. Xie, D. Feng, H. Li, C. Gong, and L. Zhen, “Shape-controlled synthesis of zinc phosphate nanostructures by an aqueous solution route at room temperature,” Mater Lett , vol. 82, pp. 26–28, Sep. 2012, DOI: 10.1016/j.matlet.2012.05.037 . D. Yue, W. Lu, C. Li, X. Zhang, C. Liu, and Z. Wang, “Controllable synthesis of Ln3+ (Ln = Tb, Eu) doped zinc phosphate nano-/micro-structured materials: phase, morphology and luminescence properties,” Nanoscale , vol. 6, no. 4, p. 2137, 2014, DOI: 10.1039/c3nr03749e . X. Zhou et al. , “Synthesis of zinc phosphate and zinc ammonium phosphate nanostructures with different morphologies through pH control,” Mater Charact , vol. 108, pp. 22–28, Oct. 2015, DOI: 10.1016/j.matchar.2015.08.012 . X. Yuan, B. Zhu, X. Ma, G. Tong, Y. Su, and X. Zhu, “Low Temperature and Template-Free Synthesis of Hollow Hydroxy Zinc Phosphate Nanospheres and Their Application in Drug Delivery,” Langmuir , vol. 29, no. 39, pp. 12275–12283, Oct. 2013, DOI: 10.1021/la402743b . B. Yan and X. Xiao, “Hydrothermal synthesis, controlled microstructure, and photoluminescence of hydrated Zn3(PO4)2: Eu3 + nanorods and nanoparticles,” Journal of Nanoparticle Research , vol. 11, no. 8, pp. 2125–2135, Nov. 2009, DOI: 10.1007/s11051-008-9578-6 . G. ’Dasgupta, P. ’Schug, K. ’Christian, Analytical Chemistry , 7th ed. Wiley, 2013. C. Shi, Y. Shao, Y. Wang, G. Meng, and B. Liu, “Influence of submicron-sheet zinc phosphate synthesised by sol–gel method on anticorrosion of epoxy coating,” Prog Org Coat , vol. 117, pp. 102–117, Apr. 2018, DOI: 10.1016/j.porgcoat.2018.01.008 . X. Chen, Z. Yang, L. Wang, and H. Qin, “Synthesis of rose-like ZnAl-LDH and its application in zinc–nickel secondary battery,” Nanotechnology , vol. 30, no. 1, p. 015602, Jan. 2019, DOI: 10.1088/1361-6528/aae56e . A. Samadi-Maybodi and S. K. H. Nejad-Darzi, “Shape-selective production of zinc phosphate in aqueous and nonaqueous media using (2-hydroxyethyl) trimethylammonium hydroxide-assisted sonochemical route,” Journal of the Iranian Chemical Society , vol. 9, no. 4, pp. 431–439, Aug. 2012, DOI: 10.1007/s13738-011-0053-4 . N. Enomoto, T. Koyano, and Z. Nakagawa, “Effect of ultrasound on synthesis of spherical silica,” Ultrason Sonochem , vol. 3, no. 2, pp. S105–S109, Jul. 1996, DOI: 10.1016/1350-1477(96)00004-W . P. K. S. Mural, G. Madras, and S. Bose, “Polymeric membranes derived from immiscible blends with hierarchical porous structures, tailored bio-interfaces and enhanced flux: Potential and key challenges,” Nano-Structures & Nano-Objects , vol. 14, pp. 149–165, Apr. 2018, DOI: 10.1016/j.nanoso.2018.02.002 . T. Nishinaga, Ed., Handbook of Crystal Growth . Tokyo: Elsevier, 2015. DOI: 10.1016/C2011-0-04376-4 . G. Dhanaraj, K. Byrappa, V. Prasad, and M. Dudley, Eds., Springer Handbook of Crystal Growth . Berlin, Heidelberg: Springer Berlin Heidelberg, 2010. DOI: 10.1007/978-3-540-74761-1 . Y. Chen, “Synthesis of Rose-Like Sheet Zinc Phosphate by the Induction- Calcination Method and Its Application as a Corrosion Inhibitor in Coatings,” Int J Electrochem Sci , p. ArticleID:210456, Apr. 2021, DOI: 10.20964/2021.04.63 . S. Kamble, S. Agrawal, S. Cherumukkil, V. Sharma, R. V. Jasra, and P. Munshi, “Revisiting Zeta Potential, the Key Feature of Interfacial Phenomena, with Applications and Recent Advancements,” ChemistrySelect , vol. 7, no. 1, p. e202103084, 2022, DOI: https://DOI.org/10.1002/slct.202103084 . M.-Q. Wang, C. Ye, S.-J. Bao, and M.-W. Xu, “Controlled synthesis of Mn3(PO4)2 hollow spheres as biomimetic enzymes for selective detection of superoxide anions released by living cells,” Microchimica Acta , vol. 184, no. 4, pp. 1177–1184, Apr. 2017, DOI: 10.1007/s00604-017-2112-8 . T. Luxbacher, The Zeta Potential for Solid Surface Analysis . Austria: Anton Paar GmbH, 2014. G. W. Lu and P. Gao, “Emulsions and Microemulsions for Topical and Transdermal Drug Delivery,” in Handbook of Non-Invasive Drug Delivery Systems , Elsevier, 2010, pp. 59–94. DOI: 10.1016/B978-0-8155-2025-2.10003-4 . Additional Declarations No competing interests reported. Supplementary Files image1.png Graphical abstract Supplementarymaterial.docx Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-6908597","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":477125852,"identity":"e178496f-6336-443e-af2b-d7ff51f4da0a","order_by":0,"name":"Benjamín Valdez-Salas","email":"","orcid":"","institution":"Instituto de Ingeniería, Universidad Autónoma de Baja California","correspondingAuthor":false,"prefix":"","firstName":"Benjamín","middleName":"","lastName":"Valdez-Salas","suffix":""},{"id":477125853,"identity":"f1679edb-aaad-4d34-a90c-d920338d0e86","order_by":1,"name":"Karen Guillén-Carvajal","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA40lEQVRIiWNgGAWjYBACCSA+8KCAgYGfgYENJMDYQJSWBAMGBskGUrQwgLQYHCBWi2T/GkOgLTZ5xjeSnz34wWAju+EAd5oEPi3SEm8MgFrSis1upJkb9jCkGW84wLvZAJ8WOYkzIC2HE7fdSDCTZmA4nAjUsvEBEVr+J26ekf4NqOU/SMuGA3gdxt8D0nIgcYNEDsiWA4RtkZzBVgDUkpw448ybcsMeg2TjmYcJ+EXi/OHNHz5U2CX2t6dve/Cjwk6273jvNrwhxiCRgMwDGc+MVz0Q8B8gpGIUjIJRMApGPAAAZDBQfdQuEFEAAAAASUVORK5CYII=","orcid":"","institution":"Instituto de Ingeniería, Universidad Autónoma de Baja California","correspondingAuthor":true,"prefix":"","firstName":"Karen","middleName":"","lastName":"Guillén-Carvajal","suffix":""},{"id":477125854,"identity":"906ba31c-2a81-4fa2-9ad0-2febbec2f3cf","order_by":2,"name":"Ernesto Beltrán-Partida","email":"","orcid":"","institution":"Instituto de Ingeniería, Universidad Autónoma de Baja California","correspondingAuthor":false,"prefix":"","firstName":"Ernesto","middleName":"","lastName":"Beltrán-Partida","suffix":""},{"id":477125855,"identity":"e2f1aa03-4452-430d-9e51-ece0309f64ce","order_by":3,"name":"Jorge Salvador-Carlos","email":"","orcid":"","institution":"Instituto de Ingeniería, Universidad Autónoma de Baja California","correspondingAuthor":false,"prefix":"","firstName":"Jorge","middleName":"","lastName":"Salvador-Carlos","suffix":""},{"id":477125856,"identity":"857a45b0-cb8c-4073-a51d-683503d2ffb1","order_by":4,"name":"Mario Curiel-Álvarez","email":"","orcid":"","institution":"Instituto de Ingeniería, Universidad Autónoma de Baja California","correspondingAuthor":false,"prefix":"","firstName":"Mario","middleName":"","lastName":"Curiel-Álvarez","suffix":""},{"id":477125857,"identity":"b95a855d-1122-440c-a838-26ce3a04b0f1","order_by":5,"name":"Nicola Nedev","email":"","orcid":"","institution":"Instituto de Ingeniería, Universidad Autónoma de Baja California","correspondingAuthor":false,"prefix":"","firstName":"Nicola","middleName":"","lastName":"Nedev","suffix":""}],"badges":[],"createdAt":"2025-06-16 21:23:13","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6908597/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6908597/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":85681018,"identity":"5ee1b5ca-7ef5-4633-86bd-14faf3c56f87","added_by":"auto","created_at":"2025-06-30 15:15:54","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":525596,"visible":true,"origin":"","legend":"\u003cp\u003eProcedure for the chemical synthesis in acidic and alkaline media of ZnPCMPs and ZnPs. Created with Biorender\u003c/p\u003e","description":"","filename":"image2.png","url":"https://assets-eu.researchsquare.com/files/rs-6908597/v1/2cf6b3da44b21f48809fb716.png"},{"id":85681020,"identity":"a165ae95-570e-4250-ba9f-f54093535bea","added_by":"auto","created_at":"2025-06-30 15:15:54","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":646194,"visible":true,"origin":"","legend":"\u003cp\u003eSEM micrographs resulting from the preliminary synthesis in the chemical scheme both in alkaline (pH 8.5) and acidic (pH 4.2) media of ZnPMCPs and ZnPNPs\u003c/p\u003e","description":"","filename":"image3.png","url":"https://assets-eu.researchsquare.com/files/rs-6908597/v1/1404dd1e36f973550cc2e8ce.png"},{"id":85682187,"identity":"b9e4f700-e361-40ab-95ff-41d5fec9e446","added_by":"auto","created_at":"2025-06-30 15:23:54","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":509416,"visible":true,"origin":"","legend":"\u003cp\u003eTypes of morphologies obtained in ZnP at different pH of the medium according to Zhou et al and Yue et al [20], [21]. Created with Biorender\u003c/p\u003e","description":"","filename":"image4.png","url":"https://assets-eu.researchsquare.com/files/rs-6908597/v1/4fe1808255c8f3a4aa759cbe.png"},{"id":85679990,"identity":"7eef2e02-88ac-4b91-9025-fe9aea05b9da","added_by":"auto","created_at":"2025-06-30 15:07:55","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":552167,"visible":true,"origin":"","legend":"\u003cp\u003eSynthesis route of MCPs and NPs according to the reaction medium. Created with Biorender\u003c/p\u003e","description":"","filename":"image5.png","url":"https://assets-eu.researchsquare.com/files/rs-6908597/v1/f82946cc2fcc22a6f65ec665.png"},{"id":85680002,"identity":"57c8d199-24f4-485b-b6dc-09e3ac135c9d","added_by":"auto","created_at":"2025-06-30 15:07:55","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":444616,"visible":true,"origin":"","legend":"\u003cp\u003eSize distribution of NPs and MCPs obtained in acidic and alkaline media, using AC and HCl. B = Alkaline medium\u003c/p\u003e","description":"","filename":"image6.png","url":"https://assets-eu.researchsquare.com/files/rs-6908597/v1/e7ff810c0460a762e090a852.png"},{"id":85681023,"identity":"76b41dbb-998f-4598-b704-4f28e6212dab","added_by":"auto","created_at":"2025-06-30 15:15:55","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":285096,"visible":true,"origin":"","legend":"\u003cp\u003eParticle size distribution and zeta potential of 1HCl and IBAC\u003c/p\u003e","description":"","filename":"image7.png","url":"https://assets-eu.researchsquare.com/files/rs-6908597/v1/c60bcee18c9dda85aab26254.png"},{"id":91001432,"identity":"35d85dc7-384c-4825-bb80-470afb9e61c3","added_by":"auto","created_at":"2025-09-10 13:47:12","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":3904071,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6908597/v1/fc4c1131-f779-43ea-98ab-8c08053aec03.pdf"},{"id":85679984,"identity":"5dc2862f-3485-443e-af03-2ce1811c0695","added_by":"auto","created_at":"2025-06-30 15:07:54","extension":"png","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":562852,"visible":true,"origin":"","legend":"\u003cp\u003e\u003cstrong\u003eGraphical abstract\u003c/strong\u003e\u003c/p\u003e","description":"","filename":"image1.png","url":"https://assets-eu.researchsquare.com/files/rs-6908597/v1/e7776c5ed4667748903f1b88.png"},{"id":85679989,"identity":"a83acd7d-af47-44ee-9297-13ac13db2d4e","added_by":"auto","created_at":"2025-06-30 15:07:54","extension":"docx","order_by":2,"title":"","display":"","copyAsset":false,"role":"supplement","size":161295,"visible":true,"origin":"","legend":"","description":"","filename":"Supplementarymaterial.docx","url":"https://assets-eu.researchsquare.com/files/rs-6908597/v1/db2504dddbfcb26bb8410459.docx"}],"financialInterests":"No competing interests reported.","formattedTitle":"Synthesis of stable zinc-phosphate micro/nanoparticles under acid and alkaline conditions","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eInorganic microparticles (MCPs) and nanoparticles (NPs) are materials composed of metallic and ceramic elements. These types of compounds exhibit good biocompatibility, hydrophilicity, non-toxicity, stability, electrical, and optical properties, with respect to their counterparts without controlled physicochemical modifications [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e], [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eAmong the wide variety of MCPs and inorganic NPs, \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:Z{n}_{3}({{PO}_{4})}_{2}\\)\u003c/span\u003e\u003c/span\u003e presents interesting properties as serve as an effective anticorrosive coating [\u003cspan additionalcitationids=\"CR4 CR5 CR6\" citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e]-[\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e], as an additive in paints [\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e], [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e], as well as in controlled drug delivery systems [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e], [\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]. However, it is important to highlight that these materials, both in bulk and nanostructured configurations, are collected and used in powder form since it is not soluble at pH above 7.16 [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]. The precipitation of this white powder serves as a clear indicator of the formation and poor stability of the material.\u003c/p\u003e \u003cp\u003eOne of the most common methods for solubilizing phosphate materials is by using microorganisms that can perform various routes of action, such as the production of a siderophore, utilizing the phytase enzyme, or generating acids and H\u003csup\u003e+\u003c/sup\u003e ions [\u003cspan additionalcitationids=\"CR14\" citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]-[\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. In the case of the latter mentioned method, the phosphate is converted into a soluble form, like the case of phosphoric acid, \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{H}_{3}{PO}_{4};\\)\u003c/span\u003e\u003c/span\u003e where the metal is coupled to the acid or remains in divalent or trivalent form; in contrast, the phosphate remains in orthophosphate form [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e]. Thus, when \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:Z{n}_{3}({{PO}_{4})}_{2}\\)\u003c/span\u003e\u003c/span\u003e is in contact with the acid media, a primary product is formed between these two compounds. The subsequent chain of additional reactions leading to a decay in solubility and the final formation of amorphous zinc orthophosphate has a very low solubility in water. [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e], [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e], [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eTherefore, in the present work, we design the synthesis of \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:Z{n}_{3}({{PO}_{4})}_{2}\\)\u003c/span\u003e\u003c/span\u003e (ZnP) micro and nanoparticles by varying the pH, we aimed to analyze their stability in aqueous media. For this purpose, we applied three acidic media; citric acid (CA), hydrochloric acid (HCl) and ascorbic acid (AA); and a basic medium of ammonium hydroxide, as along with different surfactant concentrations. This synthetic strategy presents a promising route for the controlled formation of ceramic micro/nanoparticles with significant implications for stability in relation to pH and synthesis medium.\u003c/p\u003e"},{"header":"2. Materials and methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003e2.1 Materials\u003c/h2\u003e \u003cp\u003eThe zinc chloride (\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:Zn{Cl}_{2}\\)\u003c/span\u003e\u003c/span\u003e), and monopotassium phosphate (\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:K{H}_{2}{PO}_{4})\\)\u003c/span\u003e\u003c/span\u003e were purchased from FAGALab, Mexico; the ascorbic acid (AA) from Fisher, Mexico; hydrochloric acid (\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:HCl)\\)\u003c/span\u003e\u003c/span\u003e and ammonium hydroxide (N\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{H}_{4}OH)\\)\u003c/span\u003e\u003c/span\u003e from Baker, Mexico; Cocobetaine (CC) from Chemie NRW, Mexico; and citric acid (AC) from Fermont, Mexico.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003e2.2 Method\u003c/h2\u003e \u003cdiv id=\"Sec5\" class=\"Section3\"\u003e \u003ch2\u003e2.2.1 Synthesis of ZnPNPs by chemical method\u003c/h2\u003e \u003cp\u003eThe experimental zinc phosphate micro- and nanoparticles (ZnPMCNPs and ZnPNPs) were synthesized by chemical method in acidic and a separate alkaline medium using a surfactant to stabilize at concentrations of 0.1%, 0.5% and 1% (w/v). Initially, 2.5 mL of the surfactant solution were placed in a glass vessel and ultrasonicated for 5 min using an ultrasonic bath (BRANSON) at a 22 kHz frequency and an amplitude of 40%. Then, in three separate vessels we added 5 mL of a 0.05 M \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:Zn{Cl}_{2}\\)\u003c/span\u003e\u003c/span\u003e aqueous solution and one of the three acidic media (HCl 10% (w/w), AC 10% (w/w) and AA 10% (w/w)) until obtaining a pH of 4. Then, the solution was mixed for 10 min and subsequently 5 mL of a 0.025 M \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:K{H}_{2}{PO}_{4}\\)\u003c/span\u003e\u003c/span\u003e solution was added dropwise and left to react for 10 min. The final pH of the solution was adjusted to pH 4.2 with the previously mentioned acidic solutions or to pH 8.5 with 10% N\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{H}_{4}OH\\)\u003c/span\u003e\u003c/span\u003e and allowed to react for 10 min. Finally, the resulting mixture was ultrasonicated for 10 min using an OMNI SONIC RUPTOR 400 unit with 22 kHz frequency and 40% amplitude. For the alkaline samples, the precipitate was collected and washed three times with ethanol 70% w/w at 6,000 RPM for 10 min. After the last wash, the samples were dried in a desiccator for 48h at room temperature and resuspended. A schematic illustration of the procedure is described in Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e and in Table \u003cspan refid=\"MOESM1\" class=\"InternalRef\"\u003eS1\u003c/span\u003e are shown the corresponding labels.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section3\"\u003e \u003ch2\u003e2.2.2 Resuspension of NPs\u003c/h2\u003e \u003cp\u003eThe resuspension of MCPs and NPs was carried out by modifying the pH of the solution (up to 4.2) with the modified ZnPMCNPs and ZnPNPs, which were synthesized by using the following solutions: HCl 10% (w/w), AC 10% (w/w) and AA 10% (w/w).\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003e2.3 Nanoparticle characterization\u003c/h2\u003e \u003cp\u003eThe morphology, homogeneity and size of the synthesized MCPs and NPs were evaluated using Field Emission Scanning Electron Microscopy (FE-SEM; LYRA 3, Tescan, Brno, Czech Republic) with an accelerating voltage of 10 kV. The chemical composition was analyzed by energy dispersive X-ray spectroscopy (EDX, Bruker, Xflash 6I30, Billerica, MA, USA) coupled to FE-SEM. Prior to analysis the MCPs and NPs were taken directly from the resuspension solution with 10% HCl and placed on a double-sided adhesive carbon conductive tape and dried at room temperature. To evaluate the size distribution (hydrodynamic diameter) and zeta potential (\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:\\zeta\\:\\)\u003c/span\u003e\u003c/span\u003e) of MCPs and NPs, dynamic light scattering (DLS; Nanotrac Wave II system Microtrac, North Wales, PA, USA) was used. The resuspended solutions from the different acidic medium used (HCl 10% (w/w), AC 10% (w/w) y AA 10% (w/w)) at pH 4. 2 were previously sonicated in an ultrasonic bath (DK300PF, China) at room temperature, 120 W for 10 min, and then filtered (Whatman, No. 4). Then, the DLS were caried out using a delay time of 30 s and a run time of 30 s at room temperature [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e].\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e"},{"header":"3. Results and Discussion","content":"\u003cdiv id=\"Sec9\" class=\"Section2\"\u003e \u003ch2\u003e3.1 Morphology and growth mechanism analysis of micro/nano ZnP structures\u003c/h2\u003e \u003cp\u003eRecent works suggest that ZnPCMPs and ZnPNPs can be easily obtained through chemical methods using precursors such as zinc nitrate, dibasic sodium phosphate, dehydrogenated ammonium phosphate, zinc acetate, and ammonium phosphate. Moreover, other physicochemical parameters are applied, such as ultrasonication, high temperature, or varying the pH of the solution, commonly with a tendency to alkalinity [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e], [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e], [\u003cspan additionalcitationids=\"CR20 CR21\" citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]-[\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. These methods allow obtaining MCPs and NPs by precipitation with shapes including pyramidal hexagons, sheets, nanoflowers and hollow spheres. However, the synthesis and stabilization of these materials in the same reaction medium have not been achieved yet.\u003c/p\u003e \u003cp\u003eIn order to corroborate the formation of the MCPs and NPs before their resuspension and/or solubility increase; two samples of ZnP were meticulously analyzed by SEM-EDS under the same synthesis procedure with an initial pH of 4, and final alkaline (pH 8.5) or acidic pH (pH 4.2). The micrographs in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e show that completely different microstructures can be obtained, depending on the pH of the reaction medium, achieving an orthorhombic system formed at pH 4.2 and a spherical morphology. On the other hand, a monoclinic system was obtained at pH 8.5 with the formation of flat ovals larger than spherical particles, which agrees with previous reports in the literature [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e], [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e]. According to these analyses, we can particularly attribute the increase in pH to the changes in Zn crystal orientation preference, crystal surface lattice density, and degree of dispersion observed [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e].\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eThus, providing a reliable understanding of the role of the pH reaction medium in determining microstructure formation and crystal orientation.\u003c/p\u003e \u003cp\u003eTo explain the effect of pH on the morphological change shown, HCl (10% w/w) and NH\u003csub\u003e4\u003c/sub\u003eOH (10% w/w) solutions were considered as pH adjusting solutions according to the following reaction scheme:\u003c/p\u003e \u003cp\u003eIn solution\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:\\:K{H}_{2}P{O}_{4}\\:\\)\u003c/span\u003e\u003c/span\u003ecan ionize into \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{P{O}_{4}}^{3-}\\)\u003c/span\u003e\u003c/span\u003e, a process by which an acid, base, or a salt dissociates into ions in an aqueous solution. In the case of \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:K{H}_{2}P{O}_{4}\\)\u003c/span\u003e\u003c/span\u003e, this compound ionizes in three stages (successive protonation of the phosphate ion) according to reactions (1) to (3). Hydrolysis is the reaction of the study ion with water, generating OH\u003csup\u003e\u0026minus;\u003c/sup\u003e (in basic media) or H\u003csub\u003e3\u003c/sub\u003eO\u003csup\u003e+\u003c/sup\u003e (in acidic media). The preference between the two pathways depends on the acidity constant (\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{K}_{a})\\)\u003c/span\u003e\u003c/span\u003e and the hydrolysis constant (\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{K}_{h}\\)\u003c/span\u003e\u003c/span\u003e). In the case of \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{HP{O}_{4}}^{2-}\\:\\)\u003c/span\u003e\u003c/span\u003eit has a preference to ionize over hydrolyze (4) according to their constants (\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{K}_{a3}\u0026lt;{K}_{h})\\)\u003c/span\u003e\u003c/span\u003e [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e].\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"No\" id=\"Taba\" border=\"1\"\u003e \u003ccolgroup cols=\"3\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:K{H}_{2}P{O}_{4}\\leftrightharpoons\\:{K}^{+}+{{H}_{2}P{O}_{4}}^{-}\\)\u003c/span\u003e\u003c/span\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{K}_{a1}=7.5x{10}^{-3}\\)\u003c/span\u003e\u003c/span\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003e(1)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{{H}_{2}P{O}_{4}}^{-}\\leftrightharpoons\\:{H}^{+}+{HP{O}_{4}}^{2-}\\)\u003c/span\u003e\u003c/span\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{K}_{a2}=6.2x{10}^{-8}\\)\u003c/span\u003e\u003c/span\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e(2)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{HP{O}_{4}}^{2-}\\leftrightharpoons\\:{H}^{+}+{P{O}_{4}}^{3-}\\)\u003c/span\u003e\u003c/span\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{K}_{a3}=2.2x{10}^{-13}\\)\u003c/span\u003e\u003c/span\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e(3)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{HP{O}_{4}}^{2-}+{H}_{2}O\\leftrightharpoons\\:{{H}_{2}P{O}_{4}}^{-}+\\:{OH}^{-}\\)\u003c/span\u003e\u003c/span\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{K}_{h}=1.6x{10}^{-7}\\)\u003c/span\u003e\u003c/span\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e(4)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{{H}_{2}P{O}_{4}}^{-}+{H}_{2}O\\leftrightharpoons\\:{H}_{3}P{O}_{4}+\\:{OH}^{-}\\)\u003c/span\u003e\u003c/span\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{K}_{h}=1.3x{10}^{-12}\\)\u003c/span\u003e\u003c/span\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e(5)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{P{O}_{4}}^{3-}+{H}_{2}O\\leftrightharpoons\\:{HP{O}_{4}}^{2-}+{OH}^{-}\\:\\)\u003c/span\u003e\u003c/span\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e(6)\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eWhen the medium is acidic (pH\u0026thinsp;\u0026lt;\u0026thinsp;7), there is a preference for \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{{H}_{2}P{O}_{4}}^{-}\\)\u003c/span\u003e\u003c/span\u003e to hydrolyze over ionize according to reactions (2), (4) and (5) facilitating the stability of \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{{H}_{2}P{O}_{4}}^{-}\\:\\)\u003c/span\u003e\u003c/span\u003ebecause of \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{H}^{+}\\:\\)\u003c/span\u003e\u003c/span\u003eions, carrying out the reaction (7). In addition, the concentration of \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{P{O}_{4}}^{3-}\\)\u003c/span\u003e\u003c/span\u003e anions are reduced due to the equilibrium in the hydrolytic reaction (6) which is directed in the right-hand direction of the reaction, where these \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{P{O}_{4}}^{3-}\\)\u003c/span\u003e\u003c/span\u003e ions prefer to react with \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{Zn}^{2+}\\)\u003c/span\u003e\u003c/span\u003eions to form ZnP (8):\u003cdiv id=\"Equ1\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equ1\" name=\"EquationSource\"\u003e\n$$\\:3{Zn}^{2+}+{{6H}_{2}P{O}_{4}}^{-}\\to\\:3Zn{\\left({H}_{2}P{O}_{4}\\right)}_{2}\\to\\:{Zn}_{3}{\\left(P{O}_{4}\\right)}_{2}+4{H}_{3}P{O}_{4}$$\u003c/div\u003e\u003cdiv class=\"EquationNumber\"\u003e7\u003c/div\u003e\u003c/div\u003e\u003cdiv id=\"Equ2\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equ2\" name=\"EquationSource\"\u003e\n$$\\:3{Zn}^{2+}+{2P{O}_{4}}^{-3}\\to\\:{Zn}_{3}{\\left(P{O}_{4}\\right)}_{2}$$\u003c/div\u003e\u003cdiv class=\"EquationNumber\"\u003e8\u003c/div\u003e\u003c/div\u003e\u003c/p\u003e \u003cp\u003eAs a relatively high concentration of free H\u003csup\u003e+\u003c/sup\u003e and H\u003csub\u003e3\u003c/sub\u003eO\u003csup\u003e+\u003c/sup\u003e ions is present in contact with the ZnP, strong hydrogen bonds are formed between the contact surfaces of the Zn\u003csub\u003e3\u003c/sub\u003e(PO\u003csub\u003e4\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003e and H\u003csub\u003e2\u003c/sub\u003eO nuclei, generating an increased repulsion between them. Therefore, the resulting growth anisotropy along certain crystal planes formed nano and microbumps, with relatively small, uniform particles showing a low degree of orientation, which in our case resulted in spherical NPs and MCPs, illustrating an orthorhombic crystal system configuration [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eWhen the medium is alkaline (pH\u0026thinsp;\u0026gt;\u0026thinsp;7), the \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{HP{O}_{4}}^{2-}\\)\u003c/span\u003e\u003c/span\u003e anion remains stable due to the presence of \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{OH}^{-}\\)\u003c/span\u003e\u003c/span\u003e carrying out the reaction (9):\u003cdiv id=\"Equ3\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equ3\" name=\"EquationSource\"\u003e\n$$\\:3{Zn}^{2+}+{2HP{O}_{4}}^{2-}+2{OH}^{-}\\to\\:{Zn}_{3}{\\left(P{O}_{4}\\right)}_{2}+2{H}_{2}O$$\u003c/div\u003e\u003cdiv class=\"EquationNumber\"\u003e9\u003c/div\u003e\u003c/div\u003e\u003c/p\u003e \u003cp\u003eIf the pH value\u0026thinsp;\u0026gt;\u0026thinsp;8 to 8.5, the concentration of \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{OH}^{-}\\:\\)\u003c/span\u003e\u003c/span\u003eis slightly higher than \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{H}^{+}\\)\u003c/span\u003e\u003c/span\u003e ions in the reaction medium; thus, the concentration of \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{P{O}_{4}}^{3-}\\)\u003c/span\u003e\u003c/span\u003e anions increase due to the leftward lean of the hydrolytic reaction equilibrium (6). Thus, one can have not only the reaction between \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{P{O}_{4}}^{3-}\\)\u003c/span\u003e\u003c/span\u003e and \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{Zn}^{2+}\\)\u003c/span\u003e\u003c/span\u003e but also with \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{N{H}_{4}}^{+}\\)\u003c/span\u003e\u003c/span\u003e cations due to the pH adjustment from \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:N{H}_{4}OH\\)\u003c/span\u003e\u003c/span\u003e, thus forming zinc ammonium phosphate (\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:N{H}_{4}ZnP{O}_{4}\\)\u003c/span\u003e\u003c/span\u003e). Nonetheless, since our initial reaction medium was acidic, there was a larger amount of \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{H}^{+}\\)\u003c/span\u003e\u003c/span\u003e ions available, thus not allowing the formation of \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:N{H}_{4}ZnP{O}_{4}\\)\u003c/span\u003e\u003c/span\u003e, as shown in the EDS analysis, which only contemplates the presence of Zn, P, O and a trace of C (Figure \u003cspan refid=\"MOESM1\" class=\"InternalRef\"\u003eS1\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eIn this sense, it is important to highlight that by applying this synthetic strategy we can obtain ZnP micro and nanoparticles with improved physicochemical control without requiring the purification of the reaction medium to eliminate the \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:N{H}_{4}ZnP{O}_{4}\\)\u003c/span\u003e\u003c/span\u003e. On the other hand, the MCNPs and NPs in the alkaline medium synthesized in this work presented a homogeneous and stable final structure. Micro/nanosheets were generated that assembled radially from the center outwards, increasing in width with the integration of multiple layers, following a crystal growth orientation that generated an oval-flat monoclinic shape [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. This is due to the change in the traditional synthesis methods in the alkaline medium where they give rise to the characteristic spikes, sheets or microflowers [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e], [\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e], [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e] attributed to the complex equilibrium between the ions in the reaction system and the adsorption of ions on the different faces of the crystal. The formation of sheets is mainly influenced by \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{HP{O}_{4}}^{2-}\\)\u003c/span\u003e\u003c/span\u003e ions, and not by \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{{H}_{2}P{O}_{4}}^{-}\\)\u003c/span\u003e\u003c/span\u003e, as observed in our reaction, due to a lower concentration of free \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{H}^{+}\\)\u003c/span\u003e\u003c/span\u003e with a lower repulsion between the crystal surfaces generating a higher agglomeration [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e], [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. Therefore, an increase in the pH of the reaction system affects the stability of the ions due to the equilibrium between ionization and hydrolysis, resulting mainly in small self-assembling lamellar crystals along one direction of the crystalline plane. It is important to highlight that we obtained smaller particles sizes than those reported in the literature, even at similar final pH conditions as shown in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eSize of ZnPCMPs and ZnPNPs according to different works\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"7\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003epH m\u0026eacute;dium\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eLength (\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:\\mu\\:m)\\)\u003c/span\u003e\u003c/span\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eWidth (\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:\\mu\\:m)\\)\u003c/span\u003e\u003c/span\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eThickness (\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:\\mu\\:m)\\)\u003c/span\u003e\u003c/span\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eSize (\u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:\\mu\\:m)\\)\u003c/span\u003e\u003c/span\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eStructure\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003eReference\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003e2.6\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cem\u003e1.5\u0026ndash;1.8\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u003cem\u003eMicrosheet\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e[\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003e3\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cem\u003e~\u0026thinsp;10.6\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003e~\u0026thinsp;6.1\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cem\u003e0.050\u0026ndash;0.1\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u003cem\u003eNanosheet\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e[\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003e3\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cem\u003e0.1\u0026ndash;1.8\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003e-\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u003cem\u003eMicrosheet\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e[\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003e3.5\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cem\u003e0.9\u0026ndash;1.5\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003e0.6\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cb\u003e-\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u003cem\u003eOrthorhombic\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e[\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003e4\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cem\u003e~\u0026thinsp;20.3\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003e~\u0026thinsp;10.4\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cem\u003e~\u0026thinsp;0.2\u0026ndash;0.5\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u003cem\u003eMicroplates\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e[\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003e4\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cem\u003e0.3\u0026ndash;2.5\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003e0.2\u0026ndash;1.5\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u003cem\u003eMicroflower\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e[\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003e4\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cem\u003e~\u0026thinsp;7\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u003cem\u003eMicroflower\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e[\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003e5\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cem\u003e9.8\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u003cem\u003eMicroflower\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e[\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003e5\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cem\u003e0.2\u0026ndash;0.8\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u003cem\u003eMicrosheet\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e[\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003e5\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cem\u003e2\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u003cem\u003eMicrosheet\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e[\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003e6\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cem\u003e~\u0026thinsp;0.05\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cem\u003e~\u0026thinsp;6\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u003cem\u003eMicrosphere\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e[\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003e6\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cem\u003e11\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u003cem\u003eMicroflower\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e[\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003e6\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cem\u003e~\u0026thinsp;4\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003e~\u0026thinsp;3\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cem\u003e~\u0026thinsp;0.08\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u003cem\u003eNanosheet\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e[\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003e6.5\u0026ndash;7\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u003cem\u003eMicroflower\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e[\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003e7\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cem\u003e~\u0026thinsp;10.1\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u003cem\u003eMixture (flower, bipyramid, prism)\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e[\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003e7\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cem\u003e0.0036\u0026ndash;0.04\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u003cem\u003eNanosphere\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e[\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003e7\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cem\u003e~\u0026thinsp;3.8\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u003cem\u003eMicroflower\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e[\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003e\u0026gt;\u0026thinsp;7.2\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cem\u003e1.43\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u003cem\u003eHexagonal bipyramid\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e[\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003e\u0026gt;\u0026thinsp;7.2\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cem\u003e1.5\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u003cem\u003ePlatelike\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e[\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003e8\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cem\u003e8.8\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cem\u003e0.04\u0026ndash;0.9\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u003cem\u003eFlower\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e[\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003e8\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cem\u003e10\u0026ndash;12\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u003cem\u003eMixture (orthorhombic, monoclinic and dandelion)\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e[\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003e8.5\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cem\u003e0.2\u0026ndash;0.5\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003e6\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u003cem\u003eMultilayer nanosheet\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e[\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003e9\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cem\u003e9\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u003cem\u003eMicroflower\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e[\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003e9\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cem\u003e(1.3 x 1 x 0.5)\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u003cem\u003eMicrocube\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e[\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003e10\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u003cem\u003eMicroflower\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e[\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003e11\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cem\u003e2\u0026ndash;8\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u003cem\u003eMicroflower\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e[\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003e11\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u003cem\u003eIrregular NPs\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e[\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003eAlkali\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cem\u003e0.2\u0026ndash;0.5\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u003cem\u003eAmorphous\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e[\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e]\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003e4.2\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cem\u003e0.06\u0026ndash;0.3\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u003cem\u003eSphere\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e\u003cem\u003eThis work\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003e\u003cem\u003e8.2\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cem\u003e1.65\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cem\u003e0.12\u0026ndash;0.14\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e\u003cem\u003e-\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u003cem\u003eOval-flat\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e\u003cem\u003eThis work\u003c/em\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eAccording to Zhou et al and Yue et al [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e], [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e], particles obtained in acidic media (pH\u0026thinsp;\u0026lt;\u0026thinsp;3), have a higher degree of orientation that enables the formation of complete and long lamellar crystals. Meanwhile, at pH 4 relatively small and almost uniform particles with low degree of orientation can be obtained. In contrast, at pH levels from 5 to 6 flower structures with sizes between 9.8 to 11 \u0026micro;m are formed, for p. However, the sizes detected are around 8.8 and 9 \u0026micro;m in pH 8 and 9, where in the latter the multiple layers in each of the petals can be observed. Likewise, for \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:N{H}_{4}ZnP{O}_{4}\\)\u003c/span\u003e\u003c/span\u003e, sheet structures can be obtained at pH 8.5 and cube structures at pH 9. Finally, at pH 10 and 11, the product obtained demonstrates a structure of nanowires and sheets/nanospikes differ from each other or are spherical when it comes to \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:N{H}_{4}ZnP{O}_{4}\\)\u003c/span\u003e\u003c/span\u003e. Figure\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e shows a scheme illustrating the previously mentioned information. Based on our results, we suggest that the pH value is possibly the most important factor in controlling the reaction course undergone by ZnP micro/nanparticulate materials, as a modulator of the size and the structural morphology.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eLikewise, it has been mentioned that the sonicating process increases the nucleation rate, which causes an increase in crystallization, and therefore, in crystal growth when synthesizing ZnPMCPs and ZnPNPs [\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e] being this agglomeration much lower when resuspension is performed [\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]. For this reason, the sheets usually have measurements that are no longer considered nanometric. In our process we performed the two previous points, so we obtained better oval sheets and then in the resuspension process these had smaller sizes, allowing us to describe a synthetic strategy for the control in the micro/nanostructured size.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec10\" class=\"Section2\"\u003e \u003ch2\u003e3.2 Synthesis mechanism\u003c/h2\u003e \u003cp\u003eA schematic diagram of the formation of the spherical and flat oval structures of ZnP in acidic and alkaline media, respectively, is shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e. The aqueous surfactant solution (CC), upon exposure to ultrasonic irradiation initiates self-aggregation to form spherical micelle structures. Since the CC contains an amphoteric surfactant, it can attract Zn\u003csup\u003e+\u0026thinsp;2\u003c/sup\u003e ions to the surface of the micelles. These adsorbed micelles of zinc ions provide nucleation domains for the subsequent reaction between Zn\u003csup\u003e+\u0026thinsp;2\u003c/sup\u003e and PO\u003csub\u003e4\u003c/sub\u003e\u003csup\u003e3\u0026minus;\u003c/sup\u003e ions [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. Additionally, heating caused by ultrasonic vibration can facilitate the generation of crystalline nuclei, resulting in a uniformly distributed accumulation in solution. Producing uniform crystalline grains with growth in all directions equally, following the shape of the micelle formed by the surfactant [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e], [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eBased on Oswald ripening, which is a thermodynamic phenomenon that results in the growth of large droplets through the coalescence of smaller droplets [\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e], the larger ZnP grains grow, while the smaller grains continue to dissolve, thus producing uniform particle sizes in the ZnP crystals. Under acidic conditions, the concentration of free \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{H}^{+}\\)\u003c/span\u003e\u003c/span\u003e ions formed strong hydrogen bonds between the contact surfaces of ZnP nuclei and water, generating strong repulsion between these nuclei. In this way, growth in some planes with respect to another is prohibited, leading to the formation of microbumps [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e], [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e], [\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eSimilarly, as demonstrated in this study, with an increase in the pH of the reaction system, the stability of the ions is affected, forming small oval-shaped crystals, probably attributed to the controlled concentrations of \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{HP{O}_{4}}^{2-}\\)\u003c/span\u003e\u003c/span\u003e and \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{{H}_{2}P{O}_{4}}^{-}\\)\u003c/span\u003e\u003c/span\u003e at different pH. Since the small sheet-like crystals have a large specific surface area and the corresponding surface tension had a reduced driving force, then the small particles accumulated spontaneously, demonstrating significant self-assembly ability [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e], [\u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e], [\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e].\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003e3.3 DLS and resuspension\u003c/h2\u003e \u003cp\u003eThe ZnPCMPs generated the characteristic precipitate of the bioceramic materials by the formation of the compounds \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{Zn}_{3}{\\left({PO}_{4}\\right)}_{2}\\)\u003c/span\u003e\u003c/span\u003e in an alkaline medium, except for the ZnMCPs and ZnPNPs which were synthesized in an acidic medium. To analyze the particle and \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:\\zeta\\:\\)\u003c/span\u003e\u003c/span\u003e sizes of each synthesis, resuspension was performed according to Tables S2 and S3. Thus, the most satisfactory results in terms of resuspension and yield were obtained when an acidic medium was used, especially with the 10% HCl solution.\u003c/p\u003e \u003cp\u003eAccording to the results (Table S4), using the AC solution as the resuspension medium, it is evident that the lower the amount of surfactant, the enhanced the tendency for the formation of CMPs and NPs. In contrast, using the AA solution a greater amount of surfactant is necessary, and in turn a greater amount of acid is needed to carry out the resuspension, which is in correspondence with an increase in the size of ZnP. Therefore, this behavior explains that the presence of NPs was reduced by the strong ionization of \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:{Zn}_{3}{\\left({PO}_{4}\\right)}_{2}\\)\u003c/span\u003e\u003c/span\u003e in Zn\u003csup\u003e2+\u003c/sup\u003e and PO\u003csub\u003e4\u003c/sub\u003e\u0026thinsp;\u003csup\u003e\u0026minus;\u0026thinsp;3\u003c/sup\u003e but with little nucleation.\u003c/p\u003e \u003cp\u003eOn the other hand, according to the particle size distribution, and the potential \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:\\zeta\\:\\)\u003c/span\u003e\u003c/span\u003e (Table\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e, Fig.\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003e and Figure \u003cspan refid=\"MOESM1\" class=\"InternalRef\"\u003eS1\u003c/span\u003e), it is not convenient to resuspend with AA solution since, although it is a good reductant, when using an excess amount needed in the resuspension, it tends to form clusters and increase the particle size. Thus showing a low potential value characteristic of an unstable colloidal solution (+\u0026thinsp;4.6 mV for the AA solution using 0.5% CC (2AA) and \u0026minus;\u0026thinsp;9.1 mV for the alkaline solution of resuspended with AA using 1% CC (1BAA)). In the case of the AC solution using 0.1% CC (3AC) and the alkaline solution resuspended with AC using 1% CC (1BAC), two important peaks were obtained, one with a higher concentration of MCPs at sizes smaller than 300 nm and the other larger than 7 \u0026micro;m. On the other hand, the alkaline solution resuspended with AC using 0.1% CC (3BAC) obtained MCPs with a mean diameter of 322 nm. Therefore, when the concentration of the surfactant CC is 1% in the presence of AC, a dispersed size distribution is obtained, while at 0.1%, it presents a mostly homogeneous distribution. The higher the surfactant concentration with the use of a weak acid such as AC, the size of the nanostructure increases due to greater agglomeration, which results in different size distributions. On the other hand, a lower surfactant concentration in the presence of a weak acid allows the acid to act on the double layer and generate a greater stabilization without agglomeration [\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e], [\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e], [\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e].\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eCharacteristic values of each resuspended solution by DLS. A\u0026thinsp;=\u0026thinsp;acid, B\u0026thinsp;=\u0026thinsp;Alkaline, HCl\u0026thinsp;=\u0026thinsp;hydrochloric acid, citric acid\u0026thinsp;=\u0026thinsp;AC, ascorbic acid\u0026thinsp;=\u0026thinsp;AA, and CC\u0026thinsp;=\u0026thinsp;Cocobetaine\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"4\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSoluci\u0026oacute;n\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAcr\u0026oacute;nimo\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003ePotencial Z (mV)\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eMedia (nm)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSoluci\u0026oacute;n A con AC utilizando 0.1% de CC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3AC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e+\u0026thinsp;118.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e193.4\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSoluci\u0026oacute;n A con HCl utilizando 1% de CC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1HCl\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e+\u0026thinsp;111.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e21.55\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSoluci\u0026oacute;n A con AA utilizando 1% de CC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1AA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e+\u0026thinsp;200\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e1976\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSoluci\u0026oacute;n A con AA utilizando 0.5% de CC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2AA\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e+\u0026thinsp;4.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e448 / 1179\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSoluci\u0026oacute;n B con AC utilizando 1% de CC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e1BAC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-200\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e20.37\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSoluci\u0026oacute;n B con AC utilizando 0.1% de CC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e3BAC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-200\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e322\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSoluci\u0026oacute;n B con HCl utilizando 0.5% de CC\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e2BHCl\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e-53.9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e213.2\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003eLikewise, samples 1HCl and 2BHCl (in HCl) only presented a distribution peak, of NPs smaller than 100 nm with \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:\\zeta\\:\\)\u003c/span\u003e\u003c/span\u003e of +\u0026thinsp;111.9 mV, and MCPs smaller than 250 nm with a \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:\\zeta\\:\\)\u003c/span\u003e\u003c/span\u003e of -53.9 mV, respectively. At higher CC concentration, smaller particle sizes are obtained with higher colloidal stability. In this case, a synergy between the surfactant and the strong acid is obtained, due to the amphoteric character, which significantly improves their stability. It is proposed that the mechanism of reduction and stabilization occurs by the initial capping by the surfactant. Then the decrease in the size of the NPs is carried out by breaking the agglomerated groups that have generated. Thus, allowing to achieve a balance in the double layer that allows the electrostatic repulsion between them without agglomerating [\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e], [\u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e]. It is generally appreciated that when MCPs and NPs are in acidic media, they tend to show positive zeta potential values, while in alkaline media they tend to show a negative value due to the amount of ions present in the solution of both H\u003csup\u003e+\u003c/sup\u003e and OH\u003csup\u003e\u0026minus;\u003c/sup\u003e, respectively [\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e], [\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e].\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003cp\u003eConsidering the previous results derived from \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:\\zeta\\:\\)\u003c/span\u003e\u003c/span\u003e and the size distribution of the MCPs and NPs, a second run was made using the best-performing solution in an acid medium (1HCl) and in an alkaline medium (1BAC) to validate its replicability, as well as the effect on the improvement of the filtering method. The results are shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e, where we can appreciate that there was an improvement in the arrangement and size of the NPs in 1HCl (9.31 nm). Meanwhile, in IBAC, the CMPs had larger sizes with a greater dispersion due to the appearance of more peaks, which could lead to lower stability. The volumetric mean in IBAC was 584 nm, with an area mean of 290.5 nm. Comparing with our MCPs in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e, which is before resuspending, we can appreciate an improvement in size with no precipitate formation. These results indicated that the stability of the colloidal system is enhanced, suggesting improved resistance to precipitation and potentially leading to a longer shelf life.\u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e"},{"header":"4. Conclusion","content":"\u003cp\u003eIt was possible to synthesize and stabilize aqueous zinc phosphate micro- and nanoparticles solution in both acidic and alkaline media, obtaining initially similar structures and with variations in colloidal stability. In the case of acidic solution, nanospheres are obtained using HCl and AC at pH 4.2 and with a \u003cspan class=\"InlineEquation\"\u003e\u003cspan class=\"mathinline\"\u003e\\(\\:\\zeta\\:\\)\u003c/span\u003e\u003c/span\u003e of +\u0026thinsp;111.9 mV and +\u0026thinsp;118.4 mV, respectively. In an alkaline medium, the best results were also obtained with resuspension using the AC and HCl solutions, resulting in spliced oval flake structures with micro- and nanometer thickness. The results of the present study provide a novel method for obtaining micro/nanoparticles with high colloidal stability, recoverable prior to resuspension processes, with potential applications in the design of biomedical and anticorrosion coatings.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eSupplementary information\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe online version contains supplementary material available at \u003cstrong\u003e(doi of publication)\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgments\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe thank to Instituto de Ingenier\u0026iacute;a of Universidad Aut\u0026oacute;noma de Baja California.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor Contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eConceptualization, Benjam\u0026iacute;n Valdez-Salas, andKaren Guill\u0026eacute;n-Carvajal; methodology, Benjam\u0026iacute;n Valdez-Salas, and Karen Guill\u0026eacute;n-Carvajal; investigation, Benjam\u0026iacute;n Valdez-Salas, Karen Guill\u0026eacute;n-Carvajal, and Jorge Salvador-Carlos; software, Jorge Salvador-Carlos, and Mario Curiel-Alvarez resources, Benjam\u0026iacute;n Valdez-Salas,and Karen Guill\u0026eacute;n-Carvajal; writing\u0026mdash;original draft preparation, Benjam\u0026iacute;n Valdez-Salas,Karen Guill\u0026eacute;n-Carvajal, and Ernesto Beltr\u0026aacute;n-Partida; writing\u0026mdash;review and editing, Ernesto Beltr\u0026aacute;n-Partida, Nikola Nedev, and Mario Curiel-Alvarez; supervision, Benjam\u0026iacute;n Valdez-Salas,and Ernesto Beltr\u0026aacute;n-Partida; formal analysis, Karen Guill\u0026eacute;n-Carvajal, \u0026nbsp;Jorge Salvador-Carlos, Nikola Nedev, and Ernesto Beltr\u0026aacute;n-Partida; visualization, Karen Guill\u0026eacute;n-Carvajal; \u0026nbsp;validation, Benjam\u0026iacute;n Valdez-Salas,Karen Guill\u0026eacute;n-Carvajal, and Ernesto Beltr\u0026aacute;n-Partida; project administration, Karen Guill\u0026eacute;n-Carvajal. All authors have read and agreed to the final version of the manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNo funds, grants, or other support was received.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData availability\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNo datasets were generated or analyzed during the current study.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConflict of interest\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare no conflict of interest. The authors have no financial or proprietary interest in any material discussed in this article.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll authors have read and agreed to the published version of the manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMaterials availability\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCode availability\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eW. Paul and C. P. 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DOI: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1016/B978-0-8155-2025-2.10003-4\u003c/span\u003e\u003cspan address=\"10.1016/B978-0-8155-2025-2.10003-4\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Oval-layer structure, pH-controlled synthesis, micro/nano spheres, ultrasonication, dependent structure","lastPublishedDoi":"10.21203/rs.3.rs-6908597/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6908597/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eIn the present work, we synthesize zinc-phosphate particles (Zn\u003csub\u003e3\u003c/sub\u003e(PO\u003csub\u003e4\u003c/sub\u003e)\u003csub\u003e2\u003c/sub\u003e) of micro and nanometric sizes (ZnPMCPs y ZnPNPs) through chemical reduction in acidic and alkaline conditions in order to obtain stable colloidal solutions through resuspension of the particles. In acidic media, the addition of hydrochloric acid (HCl), citric acid (AC), or ascorbic acid (AA) created spheric structures with a zeta potential superior to +100 mV. On the other hand, the addition of ammonium hydroxide (NH\u003csub\u003e4\u003c/sub\u003eOH) created oval flat-shaped structures with zeta potential lower than -53.9 mV thus showing an agglomeration tendency in alkaline media. Therefore, these findings indicate that HCl was the most effective media for resuspension, which allowed the obtention of nanoparticles with an average size smaller than 25 nm and highly stable, which makes this an easy and reproducible method. The results from this study present a new strategy for the obtention of micro/nanoparticles with high colloidal stability, which can be recovered from previous resuspension processes without losing their stability and have potential applications in the design of biomedical and anticorrosive coatings.\u003c/p\u003e","manuscriptTitle":"Synthesis of stable zinc-phosphate micro/nanoparticles under acid and alkaline conditions","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-06-30 15:07:50","doi":"10.21203/rs.3.rs-6908597/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"2be65ca2-db76-4b84-b75f-6265f3e84ee6","owner":[],"postedDate":"June 30th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2025-09-16T15:08:45+00:00","versionOfRecord":[],"versionCreatedAt":"2025-06-30 15:07:50","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-6908597","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6908597","identity":"rs-6908597","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}