Preparation and Characterization of Polyurethane Microcapsules for Controlled Release of Bendiocarb

Preparation and Characterization of Polyurethane Microcapsules for Controlled Release of Bendiocarb | 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 Preparation and Characterization of Polyurethane Microcapsules for Controlled Release of Bendiocarb Wulin Xia, yan liu, Haitao Zhou, Chao Zheng, Wenjie Yin, Tianhao Lu, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6821252/v1 This work is licensed under a CC BY 4.0 License Status: Published Journal Publication published 31 Mar, 2026 Read the published version in Journal of Polymer Research → Version 1 posted 5 You are reading this latest preprint version Abstract In this study, waterborne polyurethane (WPU) microcapsules encapsulating bendiocarb were successfully prepared by interfacial polymerization for sustainable mosquito control. A high encapsulation efficiency of 94% was achieved by systematically optimizing the emulsifier concentration (2% PVA), core-to-wall ratio (1:2), reaction temperature (50°C), and reaction time (6 h). Comprehensive characterization confirmed the uniform spherical morphology (particle size 1–3 µm), core-shell structure, and thermal stability of the microcapsules. Importantly, a core-to-wall ratio threshold of 2:1 was determined: microcapsules with core-to-wall ratios ≤ 2:1 have a dense cross-linked network that provides dual core protection (physical barrier + thermal dissipation; initial decomposition temperature T₀ ≥ 163°C), while ratios > 2:1 lead to shell discontinuities and thermal channeling (T₀ ≤ 145°C), and the protective effect of the walls on the core is lost. Long-term efficacy of the microencapsulated fabrics was demonstrated by bioassays: 27% residual drug retention after 20 washes and the drug residue after 28 days of cumulative release (at a constant temperature of 40°C) was 30.8%. This study establishes an ecologically sound framework for the targeted application of pesticides based on the World Health Organization guidelines on pesticide residues. interfacial polymerization bendiocarb polyurethane microcapsules sustained release Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 Figure 12 Figure 13 1. Introduction Mosquito-borne diseases such as malaria, dengue fever, and Zika virus persistently threaten global public health security, with malaria alone causing approximately 619,000 fatalities in 2021 1 . Conventional vector control strategies predominantly rely on synthetic insecticides including pyrethroids (e.g., permethrin) and organophosphates. However, their rapid environmental degradation, escalating mosquito resistance, and toxicity to non-target organisms have constrained their long-term efficacy 2 – 5 . To address these challenges, controlled-release formulations have emerged as sustainable solutions designed to prolong insecticidal activity while minimizing ecological impacts 6 – 8 . Among these approaches, microencapsulation technology has garnered considerable attention for its capacity to shield active ingredients from degradation while enabling tunable release kinetics 9 – 11 . Bendiocarb, a broad-spectrum insecticide advocated by the World Health Organization (WHO) for malaria intervention, displays potent activity against vectors transmitting dengue, Zika, and chikungunya viruses. However, its propensity for rapid photolytic degradation under ultraviolet radiation mandates frequent reapplications 12 – 14 . Encasing active constituents within polymeric frameworks such as polyurethane (PU) affords defense against environmental challenges while permitting extended release durations 15 , 16 . Previous investigations have examined diverse wall substances, including polyurea and polyamide 17 , 18 . Polyurethane (PU) has been extensively researched as a microencapsulation envelope material, prized for its exceptional mechanical adaptability and chemical durability 19 – 24 . Waterborne polyurethane (WPU) emerges as a prime candidate attributable to its minimal toxicity, biodegradability, and modifiable mechanical characteristics 25 – 27 . Notably, its intrinsic self-emulsifying nature diminishes the necessity for substantial emulsifiers or supplementary surfactants 28 , 29 . The interfacial polymerization methodology, producing microcapsules via gentle and swift interfacial reactions, has progressively become a principal technique in agrochemical formulation, showcasing elevated encapsulation efficiency, superior thermal performance, and outstanding sustained-release characteristics 30 – 33 . Microencapsulation enables spatiotemporally targeted pesticide delivery by leveraging dynamic supramolecular cross-linking networks and stimuli-triggered degradation pathways 34 – 36 . Illustratively, Zheng et al. (2019) engineered polylactic acid-enhanced polyurethane microcapsules through interfacial polymerization, substituting eco-compatible solvents for toxic xylene. This system yielded elevated chlorpyrifos entrapment (71.0% w/w) with extended liberation spanning 65 days. The PLA-PU hybrid wall synergistically promoted payload release via coupled diffusion-degradation processes, establishing a scalable platform for sustainable insecticide regulation 37 . Comparatively, Xu et al. (2024) synthesized foliar-adherent polyurethane microcapsules (Pro@CS-OP-10) from plant-derived materials, achieving 96.38% encapsulation efficiency with enhanced light stability. The sustained-release profile extended antifungal efficacy against Fusarium graminearum in wheat crops while mitigating acute zebrafish toxicity, pioneering an ecological fungicide design 38 . Separately, Murtaza et al. implemented emulsion extrusion microencapsulation to functionalize polyester-cotton textiles with bioactive essences (limonene, camphor, linalool, menthol, 1-octanol). Validation via GC-MS, FT-IR, and SEM confirmed formulation integrity, where menthol exhibited peak repellency (97% initial efficacy, > 89% retention at 50 days), advancing eco-conscious durable mosquito-repellent fabric engineering 39 . This investigation centers on synthesizing bendiocarb-encapsulated polyurethane microcapsules using interfacial polymerization. The resultant microcapsules underwent detailed assessment of their morphology, particle size distribution, encapsulation efficiency, and thermal performance. Anti-mosquito textiles were subsequently manufactured by proportionally combining microcapsules, binder, and JFC penetrant. The modified fabrics were appraised for laundering endurance and sustained-release performance, thereby broadening the prospective utility of microcapsules in repellent applications. By amalgamating environmentally favorable materials with stringent process refinement, this work propels sustainable vector control approaches. These efforts are consistent with worldwide efforts to reduce pesticide residues and improve environmental safety. 40 – 42 . 2. Experimental section 2.1 Materials The original drug of bendiocarb was purchased from Saefu (Henan) Agrochemical Co., Ltd. Sodium dodecyl sulfate (SDS), isophorone diisocyanate (IPDI) and ethyl acetate were purchased from Shanghai Sinopharm Chemical Reagent Co., Ltd. Polyethylene glycol (PEG400), 1,4-butanediol (BDO) and polyvinyl alcohol (PVA, 1788) were purchased from Shanghai Titan Technology Co., Ltd. 2.2 Preparation of polyurethane bendiocarb microcapsules Dissolve 4.68 g of bendiocarb in 23.5 g of ethyl acetate (bendiocarb/ethyl acetate mass ratio ≈ 1:5). Mix thoroughly and add 4.46 g of IPDI. Stir well at 25°C to form the oil phase. Separately, disperse 0.47 g of SDS in a 2% (w/v) PVA solution. Add 4 g of PEG400 and stir well at 25°C to form the aqueous phase. Add the oil phase to the aqueous phase using a homogenizer. Emulsify by high-speed stirring to form a uniform oil-in-water (O/W) emulsion. Transfer the O/W emulsion to a three-necked flask. Add 0.03 g of dibutyltin dilaurate and stir at 50°C (500 rpm) for 2 h. Add 0.91 g of BDO dropwise to the emulsion and continue stirring at 50°C (500 rpm) for an additional 2 h to facilitate microencapsulation. Centrifuge the mixture, dry the product, and isolate the polyurethane bendiocarb microcapsules. Figure 1 shows a schematic diagram of the polyurethane bendiocarb microcapsule preparation process. 2.3 Characterization 2.3.1 Encapsulation efficiency Microcapsule encapsulation efficiency (EE) was quantified employing high-performance liquid chromatography (HPLC). The protocol encompassed: 1. Quantification of Unencapsulated Bendiocarb: 0.1 g of microcapsule suspension was centrifuged at elevated speed (e.g., 12,000 rpm, 10 min). The microcapsules formed a pellet, leaving unbound bendiocarb within the supernatant, diluted using 100 ml of acetonitrile, and the chromatographic peak area corresponding to free bendiocarb (A₁) was ascertained directly via HPLC. (2) Determination of total core material: Another equal amount of microcapsule suspension was taken, and solvents (e.g., DMSO, THF, acetone) to dissolve the polyurethane shell were added, and ultrasonication was performed for 30 min to rupture the microcapsules and release the encapsulated nuclei. The shell fragments were then removed by centrifugation (12,000 rpm for 10 min), and the supernatant was taken and diluted with 100 ml of acetonitrile to determine the total core peak area (A₂) of Bendiocarb in the sample by liquid chromatography. The encapsulation efficiency was calculated using the following formula: $$\:EE\left(\%\right)=(1-\frac{{A}_{1}}{{A}_{2}})\times\:100$$ 1 where A 1 is the free bendiocarb peak area and A 2 is the total bendiocarb peak area. 2.3.2 Other Characterizations The apparent morphology of the microcapsules and microcapsule fabrics was observed using a scanning electron microscope (Hitachi Regulus 8100, Japan), and the core-shell structure of the microcapsules was observed using a transmission electron microscope (TEM, Tecnai-G20, FEI, Santa Clara, CA, USA). The uniformity of microcapsule particles was observed using a POM microscope (SBM-80I, Shanghai Weitu Optical and Electronic Technology Co., Ltd., China). The chemical structure of the microcapsules was characterized by Fourier transform infrared spectroscopy (Spectrum Two, Perkin-Elmer Inc., USA) in the wavelength range of 450 cm − 1 to 4000 cm − 1 . Enthalpy and thermal reliability of the microcapsules were measured by differential scanning calorimeter (DSC-4000, Perkin-Elmer Inc., USA). Each test was performed using a sample mass of 5 ~ 8 mg, in a nitrogen atmosphere, at temperatures ranging from 0°C to 300°C, using a heating and cooling rate of 10°C per minute. In addition, the thermal stability of the microcapsules was assessed using a thermogravimetric analyzer (TGA-4000, Perkin-Elmer Inc, USA). Measurement of the particle size distribution of microcapsules using a laser particle size analyzer (LS-POP 6, Zhuhai OMEC Instrument Co., Ltd., Guangdong, China). Encapsulation efficiency, water washing resistance and Sustained release efficiency were assessed by determining bendiocarb content by high performance liquid chromatography (Agilent 1200, USA). 2.4 Applications of Microencapsulation 2.4.1 Preparation of microencapsulated fabrics A 1:2 core-to-wall ratio microencapsulated suspension was used to proportionally mix the binder and JFC penetrant into a homogeneous aqueous dispersion for functional coating. The binder and JFC penetrant were mixed proportionally to form a homogeneous aqueous dispersion. Pre-cut mosquito net substrates (10 × 10 cm) were immersed in a treatment bath for 60 minutes. Subsequently, the substrate was double-layered by means of a laboratory-scale laminator at a 100% wet pick-up rate. Finally, the microencapsulated textile composites were cured by oven drying (120°C, 3 min) to obtain the microencapsulated textile composites. 2.4.2 Determination of water washing resistance and slow release efficiency Water Wash Resistance Testing: Standard Solution Preparation: Precisely weigh 0.0300 ± 0.0002 g of bendiocarb reference material into a 100-mL volumetric flask. Dilute to the mark with acetonitrile, sonicate for 10 min, allow cooling to ambient temperature, mix exhaustively, and filter. Sample Preparation: Position fabric specimens within 150 ml beakers. Accurately pipette 100 ml of acetonitrile into each beaker, seal, and sonicate for 30 min to extract the active component. The mean value serves as the analytical result. Chromatographic Determination: Under defined HPLC conditions, inject replicate sample aliquots until sequential injections exhibit < 1.0% relative peak area variability. Analyze consecutively: duplicate injections of sample solution A, duplicate injections of sample solution B. Calculate the mean peak area for each sample duplicate. Determine bendiocarb content per unit area (mg/m²) applying $$\:S=\frac{{C}_{2}mP{V}_{2}}{{C}_{1}{V}_{2}}\times\:1000÷{S}_{0}\:$$ 2 Where:C 1 :Average of the peak area of the specimen of the tested component; C 2 : Average value of the peak area of the tested component in the sample; M: Mass of the tested component specimen, g; P: the mass fraction of the tested component specimen, %; V 1 : volume of acetonitrile added to the specimen, ml; V 2 : volume of acetonitrile added in the specimen, ml; 1000: Unit conversion between grams and milligrams; S 0 : area of mosquito nets in the examined specimen, m 2 . According to the above test method, the anti-mosquito mosquito net samples were divided into 5 copies, the sample diagram as shown in Fig. 2 , representing water washing 0,, 5, 10, 15, 20 times, respectively, for liquid phase testing. A series of microencapsulated mosquito net samples(Not from the same lot as the sample used for the water washing resistance test) were prepared using the described test method to evaluate slow-release characteristics. The samples were sealed and stored at 40°C under controlled conditions, then analyzed after specified durations (0, 7, 14, 21, and 28 days) as shown in Fig. 3 . We analyzed samples from each time point using liquid chromatography. 3. Results and Discussions 3.1 Synthesis of microcapsules As shown in Fig. 4 , the microcapsules with core-to-wall ratios of 1:3 to 2:1 were mostly spherical, exhibiting uniform particle size distribution, smooth surfaces, and no obvious defects (Figs. 4 a-d). Furthermore, for microcapsules with core-to-wall ratios of 1:3 to 2:1, no cracks or pores were observed; indicating good microcapsule dispersion, absence of agglomeration, and a stable microcapsule emulsification process with sufficient interfacial polymerization reactions. When the core-to-wall ratio was increased to 3:1, Fig. 4 e shows that the surface roughness of microcapsules increased significantly, and some particles adhered, forming clusters. Figure 4 f shows the sample with a core-to-wall ratio of 4:1, where the microcapsules were severely deformed, ruptured, or collapsed, and almost completely adhered together into a block-like structure. The particle size distribution was highly non-uniform, with rupture of capsule walls or leakage of core material observable in some areas. This phenomenon occurs because at an appropriate core-to-wall ratio (1:3 − 2:1), sufficient wall material effectively encapsulates the oil-phase droplets, forming a complete cross-linking network. During emulsification, high shear forces produce uniformly sized droplets, and interfacial polymerization forms a dense capsule wall. This wall inhibits deformation or adhesion during drying and resists shrinkage stress during solvent evaporation, thereby maintaining the spherical morphology. However, at high core-to-wall ratios, the wall material cannot completely cover the larger oil-phase droplets, leading to partial exposure of the core material at the interface. This exposure causes collapse or fusion of microcapsules due to solvent evaporation during drying. Additionally, insufficient wall material may leave unreacted isocyanate groups (-NCO), which trigger chemical cross-linking between microcapsules and aggravate adhesion. Figure 5 a shows the optical micrograph of polyurethane bendiocarb microcapsules (core-to-wall ratio 1:1), revealing the spherical core-shell structure of the microcapsules. However, due to the limitations of optical microscopy in resolving nanoscale features, TEM observation is necessary. Figures 5 b, 5 c, and 5 d show TEM images of polyurethane bendiocarb microcapsules (core-to-wall ratio 1:1). These images clearly reveal the core-shell structure of the microcapsules, with bendiocarb forming the central dark region and polyurethane forming the surrounding bright region as the wall material, confirming the successful preparation of polyurethane-coated bendiocarb microcapsules. 3.2 Structural analysis of microcapsules The functional group structures of both the polyurethane bendiocarb microcapsules and pure bendiocarb were analyzed using Fourier transform infrared (FTIR) spectroscopy and the IR spectra is shown in Fig. 6 . The results showed that the telescopic vibration absorption peak of N-H in bendiocarb was at 3370.9 cm⁻¹. The peak at 2945.9 cm⁻¹ is the C-H vibration on the benzene ring of bendiocarb, and several sharp peaks appeared. The peak at 1723.4 cm⁻¹ is the superposition peak of C = O in the capsule wall (polyurethane) and bendiocarb, while at 1555.1 cm⁻¹ is the vibration peak of the benzene ring skeleton in bendiocarb, and at 1237.4 cm⁻¹ is the vibration peak of C-O-C in the capsule wall. The region 1100–1150 cm⁻¹ contains the PEG400 C-O-C peak. The strong peak at 790 cm⁻¹ corresponds to bendiocarb adjacent to the substituted benzene ring. There is no residual -NCO peak at 2270 cm⁻¹ which confirms the reaction's completion. Urethane (1725 cm⁻¹), PEG soft segment (1100–1150 cm⁻¹), and complete BDO chain expansion (no -OH peaks) indicate the success of vesicle wall synthesis. 790 cm⁻¹ (neighboring substituted benzene ring) and 1450–1600 cm⁻¹ (benzene ring backbone) clearly indicate that bendiocarb is encapsulated. No peaks appear at 2270 cm⁻¹ (confirming complete IPDI reaction) and no bendiocarb decomposition peaks (e.g., broad O-H peaks) appear. All these characteristic peaks appear simultaneously in the IR spectra of the microcapsules. 3.3 Thermal properties of microcapsules Figure 7 compares the DSC curves of polyurethane bendiocarb microcapsules and pure bendiocarb. Pure bendiocarb (Fig. 7 -a) exhibited a sharp endothermic peak at 134.1°C (Fig. 7 -b), characteristic of its melting point. The peak's symmetry and lack of shoulders indicated high crystalline purity. In contrast, the microencapsulated sample showed a broader, weaker melting peak at 128°C, a 6.1°C depression. This shift arises because bendiocarb confinement within the polyurethane matrix restricts molecular mobility, hindering regular crystal formation and promoting partial or complete amorphization. Additionally, potential H-bonding between bendiocarb's carbonyl groups (C = O) and the polyurethane's urethane linkages (-NHCOO-), alongside hydrophobic interactions, further limits molecular motion. These interactions reduce the melting entropy of bendiocarb, consequently lowering its melting point. The thermogravimetric analysis in Fig. 8 shows that the thermal decomposition behavior of the microcapsules is tightly regulated by the core-to-wall ratio: the onset decomposition temperature (T₀) of the pure polyurethane wall is 175°C (complete decomposition by 450°C), while that of the bendiocarb feedstock is 145°C (complete decomposition by 240°C). In contrast, microcapsules with core-to-wall ratios of 1:3 to 2:1 stabilized at ~ 163°C (18°C higher than the feedstock) and exhibited two-stage decomposition: core weight loss at 148–240°C and wall weight loss at 240–450°C. This results from the dense cross-linked network of the wall material forming a heat-shielding layer that protects the core and increases the activation energy for core decomposition. However, when the core-to-wall ratio increased to 3:1–4:1, T₀ plunged to 132°C (the 3:1 group approached the feedstock's 145°C), with the decomposition curve degenerating into single-phase rapid weight loss (> 80% loss at 132–240°C). This is attributed to wall material discontinuity triggering a thermal channeling effect that significantly reduces heat-shielding efficiency. Therefore, at core-to-wall ratios ≤ 2:1, the wall effectively protects the core via dual mechanisms of physical isolation and heat dissipation (T₀ ≥ 163°C), whereas at ratios > 2:1, wall defects cause collapse of the protective effect (T₀ ≤ 145°C). This 2:1 threshold establishes a critical design boundary for heat-resistant microcapsules. 3.4 Particle size and encapsulation efficiency The encapsulation efficiency and particle size of microcapsules are shown in Table 1 . Table 1 The encapsulation efficiency of microencapsulated samples with different core-to-wall ratio concentrations and particle size. Sample A 1 A 2 EE(%) Particle size (µm) 1:3 41429 311895 87 1.37 1:2 22390 368326 94 1.43 1:1 29557 427627 93 1.57 2:1 72606 445998 84 1.86 3:1 100206 498872 80 2.11 4:1 128453 557624 77 2.32 The particle size distribution is shown in Fig. 9 . It can be seen that the diameter of the microcapsules is about 1–3 µm, and the particle size of the microcapsule samples does not differ significantly. However, with increasing core-shell ratio, the particle size tends to increase. This may be attributed to the fact that higher core-shell ratios increase the proportion of core material in the oil phase while decreasing the relative content of wall monomers. Under fixed emulsification conditions (e.g., shear rate, emulsifier concentration, etc.), an increased oil-phase volume leads to larger droplets in the O/W emulsion and reduces the total amount of wall monomers. This results in decreased crosslinked network density, reduced elastic modulus of the capsule wall during curing, and greater expansion likelihood due to internal solvent (ethyl acetate) volatilization or thermal expansion, ultimately forming larger microcapsules. As shown in Fig. 10 , the encapsulation efficiency exhibits a non-monotonic trend, initially increasing then decreasing as the core-to-wall ratio increases. This result suggests that an optimal core-to-wall ratio range (1:2 − 1:1) maximizes encapsulation. At low core-to-wall ratios, higher wall material content increases crosslinking density, forming dense capsule walls with high mechanical strength that effectively prevent core leakage. However, the lower oil-phase viscosity facilitates formation of small droplets under high-shear emulsification. These droplets possess large surface areas, requiring wall material to cover more interfaces, which may cause localized thinning or defects in the capsule wall. At optimal core-to-wall ratios (1:2 − 1:1), moderate oil-phase volume increases bendiocarb solubility in ethyl acetate toward saturation, reducing precipitation risk. Sufficient wall material volume enables formation of intact capsule walls, while highly stable emulsified droplets increase encapsulation beyond 90%. At high core-to-wall ratios (above 2:1), excessive oil-phase volume may exceed the solvent's solubility limit for bendiocarb, causing core precipitation during emulsification or curing. This forms surface adsorption or defects while insufficient wall material prevents complete capsule wall formation. Reduced crosslinking density in the capsule wall increases susceptibility to rupture or leakage, significantly decreasing encapsulation rate. 3.5 Microencapsulation of finished fabrics SEM analysis (Figure.11) depicts a mosquito net fabric treated with microcapsules (core-to-wall ratio 1:2). The SEM micrograph reveals the distribution and adhesion characteristics of the capsules on the fiber substrate. Visual inspection confirms successful attachment of most microcapsules to the fiber surfaces, demonstrating effective functionalization. Furthermore, the adhered capsules exhibit a relatively uniform dispersion pattern across the fibers. This consistent distribution, avoiding localized aggregation or scarcity, indicates a well-regulated preparation process. Such process control supports stable, sustained active ingredient release in the final product. These findings validate that the microcapsules possess appropriate dimensions for fabric finishing applications. 3.6 Washing Resistance Supplementary Figure S1 and Table S1 show the wash resistance of microcapsules and residual bendiocarb content in fabric after repeated laundering. Figure 12 quantifies bendiocarb retention and loss rates post-washing. Initial drug loading (0 washes) measured 127.964 mg/m². The fabric samples experienced 47% and 70% bendiocarb loss after 5 and 10 washes, respectively, attributed primarily to rapid depletion of surface-adsorbed drug and leakage through defective capsule walls. Post-10 washes, residual drug decline markedly slowed, with merely 10.6% additional reduction after 20 washes. This stabilization confirms enhanced wash resistance, as intact microcapsule walls effectively restricted core material release. The fabric still retained 27.0% of the initial amount of drug after 20 washes, indicating that the fabric could withstand more than 20 washing cycles, which showed that the microcapsules had a certain long-lasting water washing resistance. 3.7 Sustained Release Performance Supplementary Figure S2 and Table S2 present sustained-release testing results for bendiocarb content in fabric-bound microcapsules. Initial drug loading measured 131.51 mg/m². Figure 13 quantifies bendiocarb retention and release rates over time. Following 7 days at 40°C, fabric residue declined to 113.96 mg/m² (13.4% release), primarily through diffusion of surface-adsorbed drug and rapid escape via capsule wall micropores. Cumulative release progressed to 40.5% (day 14), 61.0% (day 21), and 69.2% (day 28). Release kinetics decelerated substantially during this period, with merely 8.2% additional release between days 21–28, indicating approach toward diffusion equilibrium. A final retention of 30.8% of the initial loading after 28 days confirms significant sustained-release performance. 4. Conclusions In this study, PU microcapsules demonstrated efficacy as carriers for bendiocarb. Optimal spherical morphology (average particle size: 1.43 µm) was achieved at a 1:2 core-to-wall ratio, with 94% encapsulation efficiency. SEM/TEM and FTIR confirmed the dense cross-linked shell structure. Thermal analysis (TGA/DSC) revealed a dual-phase decomposition mechanism: the PU wall increased the onset degradation temperature of bendiocarb by 18°C, providing synergistic thermal protection. Microencapsulated functionalized fabrics retained 27% efficacy after 20 washes and exhibited 69.2% cumulative release over 28 days, outperforming conventional formulations. The core-to-wall ratio critically governs performance: ratios > 2:1 cause rapid release due to wall defects, while ratios ≤ 1:1 ensure structural integrity. This technology establishes a green paradigm for sustained mosquito control and holds critical implications for scalable production of eco-friendly agrochemicals. Declarations Conflicts of Interest The authors declare no conflict of interest. Data Availability Statement The authors confirm that the data supporting the findings of this study are available within the article. And no new data were created. AUTHOR INFORMATION Corresponding Authors Yan Liu - College of Chemistry and Chemical Engineering, Shanghai University of Engineering Science, Shanghai 201620, China; 0000-0002-1880-2664 Email: [email protected] (Y.L.) Binjie Xin - School of Textile and Fashion Engineering, Shanghai University of Engineering Science, Shanghai 201620, China; orcid.org/0000-0003-0683-8018; Email: [email protected] Authors Wulin Xia - College of Chemistry and Chemical Engineering, Shanghai University of Engineering Science, Shanghai 201620, China Haitao Zhou - College of Chemistry and Chemical Engineering, Shanghai University of Engineering Science, Shanghai 201620, China Chao Zheng - College of Chemistry and Chemical Engineering, Shanghai University of Engineering Science, Shanghai 201620, China Wenjie Yin - College of Chemistry and Chemical Engineering, Shanghai University of Engineering Science, Shanghai 201620, China Tianhao Lu - College of Chemistry and Chemical Engineering, Shanghai University of Engineering Science, Shanghai 201620, China Author Contributions The manuscript was completed by the first author. All authors reviewed the manuscript. Funding No funding was received References Al-Osaimi, H. 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R.; Vega, J.; Costa, C. A.; Galembeck, F.; Amalvy, J. I., Waterborne polyurethane/acrylate: Comparison of hybrid and blend systems. Prog Org Coat 2011, 72 (3), 429–437. Xiao, Y.; Wu, B.; Fu, X. W.; Wang, R.; Lei, J. X., Preparation of biodegradable microcapsules through an organic solvent-free interfacial polymerization method. Polym Advan Technol 2019, 30 (2), 483–488. Trojanowska, A.; Marturano, V.; Bandeira, N. A. G.; Giamberini, M.; Tylkowski, B., Smart microcapsules for precise delivery systems. Funct Mater Lett 2018, 11 (5), 1850041. Yang, M. F.; Yu, W. D.; Han, W. Y.; Wang, C. X.; Yin, Y. J., Photochromic performance optimization of polyurethane microcapsules by interfacial polymerization method. J Appl Polym Sci 2024, 141 (9), 10.1002/app.55008 . Wang, L. Y.; Liu, J.; Gao, C.; Yan, X. X.; Liu, J. Z., Preparation, Characterization, and Bioactivity Evaluation of Lambda-Cyhalothrin Microcapsules for Slow-Controlled Release System. Acs Omega 2024, 9 (7), 8229–8238. Zhao, B. Q.; Ni, Y. Z.; Chen, K. L.; Lin, Z. H.; Jia, Z. H.; Qiu, H., Double-shell lignin microcapsules were prepared by one- step method for fabric coatings with UV resistance and durable antibacterial activity. Prog Org Coat 2023, 179, 107518. Lu, S. F.; Shen, T. W.; Xing, J. W.; Song, Q. W.; Shao, J. F.; Zhang, J.; Xin, C., Preparation and characterization of cross-linked polyurethane shell microencapsulated phase change materials by interfacial polymerization. Mater Lett 2018, 211, 36–39. Jose, N.; Ray, D. P.; Misra, S.; Nayak, L.; Ammayappan, L., Microencapsulation and nanoencapsulation of fungicidal and insecticidal agents for grain packaging and storage. J Stored Prod Res 2024, 109, 102468. Zheng, T.; Chen, K.; Chen, W. Y.; Wu, B.; Sheng, Y.; Xiao, Y., Preparation and characterisation of polylactic acid modified polyurethane microcapsules for controlled-release of chlorpyrifos. J Microencapsul 2019, 36 (1), 62–71. Wang, R.; Liu, S.; Sun, F. S.; Yu, X.; Liu, X.; Li, B. X.; Mu, W.; Zhang, D. X.; Liu, F., Balance the rapid release of insecticide microcapsules using double-layer shielding effect when the foliar application. Chem Eng J 2023, 455, 140899. Murtaza, M.; Hussain, A. I.; Kamal, G. M.; Nazir, S.; Chatha, S. A. S.; Asmari, M.; Uddin, J.; Murtaza, S., Potential Applications of Microencapsulated Essential Oil Components in Mosquito Repellent Textile Finishes. Coatings 2023, 13 (8), 10.3390/coatings13081467 . Lobel, B. T.; Baiocco, D.; Al-Sharabi, M.; Routh, A. F.; Zhang, Z. B.; Cayre, O. J., Current Challenges in Microcapsule Designs and Microencapsulation Processes: A Review. Acs Appl Mater Inter 2024, 16 (31), 40326–40355. Annadurai, K. S.; Chandrasekaran, N.; Velraja, S.; Hikku, G. S.; Parvathi, V. D., Essential oil nanoemulsion: An emerging eco-friendly strategy towards mosquito control. Acta Trop 2024, 257, 107290. Mir, S. A.; Dar, B. N.; Mir, M. M.; Sofi, S. A.; Shah, M. A.; Sidiq, T.; Sunooj, K. V.; Hamdani, A. M.; Khaneghah, A. M., Current strategies for the reduction of pesticide residues in food products. J Food Compos Anal 2022, 106, 104274. Supplementary Files SupplementaryMaterials.docx Cite Share Download PDF Status: Published Journal Publication published 31 Mar, 2026 Read the published version in Journal of Polymer Research → Version 1 posted Reviewers agreed at journal 14 Jul, 2025 Reviewers invited by journal 09 Jul, 2025 Editor invited by journal 28 Jun, 2025 Editor assigned by journal 07 Jun, 2025 First submitted to journal 05 Jun, 2025 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. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. 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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-6821252","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":482773328,"identity":"07cc8e08-540d-47d8-ace5-297ea8a34f34","order_by":0,"name":"Wulin Xia","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Wulin","middleName":"","lastName":"Xia","suffix":""},{"id":482773329,"identity":"2f2f91c4-8ae9-444e-a1b1-c3945182c8d8","order_by":1,"name":"yan liu","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA5UlEQVRIie3RMQrCMBSA4VcKmSJdW4qeIRKIi3gWi9BJXFwcUwqOuuotKl4gIWCXgms366KrbnXSVpxEUt0c8kOW8L7hJQAm0x+GQEbFkLgd53Vh8SbiWComl1mfevxb4sXp3FtlYUDEt4TsJPdbczWk+6x7LKHfToR9KrQkk5xWZMLyMaUYQpoI1CNakks+qsiU5Zj5ACpIBEaulhyOXFUk2C6z3q2EezPxuIyiev0ExgwwiGbigIyhfmQ3D6c+JiO6VohpCYL0XD6/cqk213I2aC/S+KQl76tVx/5h3mQymUyfewAfDlHNugFIVwAAAABJRU5ErkJggg==","orcid":"https://orcid.org/0000-0002-1880-2664","institution":"Shanghai University of Engineering Science - Songjiang Campus: Shanghai University of Engineering Science","correspondingAuthor":true,"prefix":"","firstName":"yan","middleName":"","lastName":"liu","suffix":""},{"id":482773330,"identity":"69b100e5-435c-46d1-a281-7c95947d1d11","order_by":2,"name":"Haitao Zhou","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Haitao","middleName":"","lastName":"Zhou","suffix":""},{"id":482773331,"identity":"d5c30df3-2450-4e7c-9615-17c98afe23be","order_by":3,"name":"Chao Zheng","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Chao","middleName":"","lastName":"Zheng","suffix":""},{"id":482773332,"identity":"9b8b2089-27fd-4bac-95f1-2c9c97ef4b30","order_by":4,"name":"Wenjie Yin","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Wenjie","middleName":"","lastName":"Yin","suffix":""},{"id":482773333,"identity":"6a56ea4b-d50c-4468-80d8-625269f510c5","order_by":5,"name":"Tianhao Lu","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Tianhao","middleName":"","lastName":"Lu","suffix":""},{"id":482773334,"identity":"cdaf9b0f-16e0-4ac2-9a33-b5b6a5edd086","order_by":6,"name":"Binjie Xin","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Binjie","middleName":"","lastName":"Xin","suffix":""}],"badges":[],"createdAt":"2025-06-04 13:58:13","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6821252/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6821252/v1","draftVersion":[],"editorialEvents":[{"content":"https://doi.org/10.1007/s10965-026-04758-0","type":"published","date":"2026-03-31T15:58:55+00:00"}],"editorialNote":"","failedWorkflow":false,"files":[{"id":86522182,"identity":"63c46a23-1a78-4582-ab17-187120fd041f","added_by":"auto","created_at":"2025-07-11 15:14:53","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":108084,"visible":true,"origin":"","legend":"\u003cp\u003eSchematic diagram for preparing microcapsules by interfacial polymerization.\u003c/p\u003e","description":"","filename":"image1.png","url":"https://assets-eu.researchsquare.com/files/rs-6821252/v1/1eccd0703ac750bed3364124.png"},{"id":86522737,"identity":"0b7f73fb-a221-4c11-916b-a95159df9175","added_by":"auto","created_at":"2025-07-11 15:22:53","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":597256,"visible":true,"origin":"","legend":"\u003cp\u003eMicroencapsulated fabric samples for water washing resistance testing\u003c/p\u003e","description":"","filename":"image3.png","url":"https://assets-eu.researchsquare.com/files/rs-6821252/v1/98dce5223b12b047c15195a6.png"},{"id":86523505,"identity":"879424b7-7015-45b8-9cdf-82a330714d64","added_by":"auto","created_at":"2025-07-11 15:30:53","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":585187,"visible":true,"origin":"","legend":"\u003cp\u003eMicroencapsulated fabric samples for sustained release performance testing\u003c/p\u003e","description":"","filename":"image4.png","url":"https://assets-eu.researchsquare.com/files/rs-6821252/v1/9f1350b1958ea2c39d83bcd1.png"},{"id":86524683,"identity":"36833c89-abf3-4463-a347-bfbd8150ed31","added_by":"auto","created_at":"2025-07-11 15:38:53","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":288218,"visible":true,"origin":"","legend":"\u003cp\u003eSEM images of microcapsules with different core-shell ratios: 1:3(a), 1:2(b), 1:1(c), 2:1(d), 3:1(e), 4:1(f)\u003c/p\u003e","description":"","filename":"image5.png","url":"https://assets-eu.researchsquare.com/files/rs-6821252/v1/953d448793e5a8716c338ec3.png"},{"id":86522740,"identity":"b6d31e2b-8a6d-4576-b012-a6fb8ea454c7","added_by":"auto","created_at":"2025-07-11 15:22:53","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":287353,"visible":true,"origin":"","legend":"\u003cp\u003eOptical micrographs of microcapsules (a) and TEM images of microcapsules (b,c,d).\u003c/p\u003e","description":"","filename":"image6.png","url":"https://assets-eu.researchsquare.com/files/rs-6821252/v1/b7631c4c216578aa3eb1116d.png"},{"id":86523504,"identity":"6ec5dca3-2b70-4fc4-976a-65cdcc05a80b","added_by":"auto","created_at":"2025-07-11 15:30:53","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":566650,"visible":true,"origin":"","legend":"\u003cp\u003eFTIR spectra of polyurethane bendiocarb microcapsules (a) and Pure bendiocarb (b).\u003c/p\u003e","description":"","filename":"image7.png","url":"https://assets-eu.researchsquare.com/files/rs-6821252/v1/6e0619cbdb34c08cfea38c05.png"},{"id":86522748,"identity":"4e2edef8-a372-4a01-9297-8af78ffe997d","added_by":"auto","created_at":"2025-07-11 15:22:53","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":416013,"visible":true,"origin":"","legend":"\u003cp\u003e(a) and (b) are the DSC curves of microcapsules with different core-to-shell ratios and Pure Bendiocarb.\u003c/p\u003e","description":"","filename":"image8.png","url":"https://assets-eu.researchsquare.com/files/rs-6821252/v1/2292fe09de471e1af7861d64.png"},{"id":86522743,"identity":"67f8f354-bda4-463c-8ab3-363b5e10b9ca","added_by":"auto","created_at":"2025-07-11 15:22:53","extension":"png","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":466476,"visible":true,"origin":"","legend":"\u003cp\u003ePure polyurethane wall material and pure bendiocarb core material(a); Microcapsules with different core-to-wall ratios(b).\u003c/p\u003e","description":"","filename":"image9.png","url":"https://assets-eu.researchsquare.com/files/rs-6821252/v1/15c7cb95017e25b811f27ae3.png"},{"id":86523506,"identity":"ce941cf9-e9c2-47c6-8893-551164ed9062","added_by":"auto","created_at":"2025-07-11 15:30:53","extension":"png","order_by":9,"title":"Figure 9","display":"","copyAsset":false,"role":"figure","size":96514,"visible":true,"origin":"","legend":"\u003cp\u003eParticle size distribution of Microcapsuleswith different core-to-shell ratios\u003c/p\u003e","description":"","filename":"image10.png","url":"https://assets-eu.researchsquare.com/files/rs-6821252/v1/4f7d603e879486e45c77e873.png"},{"id":86522189,"identity":"78132111-2e27-4fef-9322-01ada3f6c82d","added_by":"auto","created_at":"2025-07-11 15:14:53","extension":"png","order_by":10,"title":"Figure 10","display":"","copyAsset":false,"role":"figure","size":87611,"visible":true,"origin":"","legend":"\u003cp\u003eLiquid phase testing of microcapsules with different core-to-shell ratio contents\u003c/p\u003e","description":"","filename":"image11.png","url":"https://assets-eu.researchsquare.com/files/rs-6821252/v1/48d58b21fe89fcf9371226a6.png"},{"id":86522194,"identity":"5158b6a4-3691-445f-bda9-a8035de900ca","added_by":"auto","created_at":"2025-07-11 15:14:53","extension":"png","order_by":11,"title":"Figure 11","display":"","copyAsset":false,"role":"figure","size":107177,"visible":true,"origin":"","legend":"\u003cp\u003eSEM image of fabrics prepared from microcapsules\u003c/p\u003e","description":"","filename":"image12.png","url":"https://assets-eu.researchsquare.com/files/rs-6821252/v1/24f15ffe9d0c6ee9b1c19764.png"},{"id":86522744,"identity":"e9812ce9-1da7-404b-99c4-624f73b92a9c","added_by":"auto","created_at":"2025-07-11 15:22:53","extension":"png","order_by":12,"title":"Figure 12","display":"","copyAsset":false,"role":"figure","size":398696,"visible":true,"origin":"","legend":"\u003cp\u003eBendiocarb content and loss rate of microencapsulated fabrics with different washing cycles\u003c/p\u003e","description":"","filename":"image13.png","url":"https://assets-eu.researchsquare.com/files/rs-6821252/v1/5a2e8a41609941ad8e2c2d57.png"},{"id":86522745,"identity":"6c5d54f1-0e6e-4237-b557-25d6b7d01b5a","added_by":"auto","created_at":"2025-07-11 15:22:53","extension":"png","order_by":13,"title":"Figure 13","display":"","copyAsset":false,"role":"figure","size":538106,"visible":true,"origin":"","legend":"\u003cp\u003eContent and loss rate of bendiocarb in microencapsulated fabrics with different slow-release cycles\u003c/p\u003e","description":"","filename":"image14.png","url":"https://assets-eu.researchsquare.com/files/rs-6821252/v1/f6f34d1e36e75bb1a225269f.png"},{"id":106343774,"identity":"2ef26513-272e-4cee-b8e0-b3115bd612fc","added_by":"auto","created_at":"2026-04-07 16:09:09","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":5425386,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6821252/v1/6fe1ab7e-a3cf-406e-9ecc-d460d5914a9d.pdf"},{"id":86522191,"identity":"e8fb71ba-c74d-482a-ad71-7ebad4e5b0f8","added_by":"auto","created_at":"2025-07-11 15:14:53","extension":"docx","order_by":4,"title":"","display":"","copyAsset":false,"role":"supplement","size":370068,"visible":true,"origin":"","legend":"","description":"","filename":"SupplementaryMaterials.docx","url":"https://assets-eu.researchsquare.com/files/rs-6821252/v1/36ef2d8253ee1621eba980d0.docx"}],"financialInterests":"","formattedTitle":"Preparation and Characterization of Polyurethane Microcapsules for Controlled Release of Bendiocarb","fulltext":[{"header":"1. Introduction","content":"\u003cp\u003eMosquito-borne diseases such as malaria, dengue fever, and Zika virus persistently threaten global public health security, with malaria alone causing approximately 619,000 fatalities in 2021\u003csup\u003e1\u003c/sup\u003e. Conventional vector control strategies predominantly rely on synthetic insecticides including pyrethroids (e.g., permethrin) and organophosphates. However, their rapid environmental degradation, escalating mosquito resistance, and toxicity to non-target organisms have constrained their long-term efficacy\u003csup\u003e\u003cspan additionalcitationids=\"CR3 CR4\" citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u003c/sup\u003e. To address these challenges, controlled-release formulations have emerged as sustainable solutions designed to prolong insecticidal activity while minimizing ecological impacts\u003csup\u003e\u003cspan additionalcitationids=\"CR7\" citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e\u003c/sup\u003e. Among these approaches, microencapsulation technology has garnered considerable attention for its capacity to shield active ingredients from degradation while enabling tunable release kinetics\u003csup\u003e\u003cspan additionalcitationids=\"CR10\" citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003eBendiocarb, a broad-spectrum insecticide advocated by the World Health Organization (WHO) for malaria intervention, displays potent activity against vectors transmitting dengue, Zika, and chikungunya viruses. However, its propensity for rapid photolytic degradation under ultraviolet radiation mandates frequent reapplications\u003csup\u003e\u003cspan additionalcitationids=\"CR13\" citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e\u003c/sup\u003e. Encasing active constituents within polymeric frameworks such as polyurethane (PU) affords defense against environmental challenges while permitting extended release durations\u003csup\u003e\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e\u003c/sup\u003e. Previous investigations have examined diverse wall substances, including polyurea and polyamide\u003csup\u003e\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e, \u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e\u003c/sup\u003e. Polyurethane (PU) has been extensively researched as a microencapsulation envelope material, prized for its exceptional mechanical adaptability and chemical durability\u003csup\u003e\u003cspan additionalcitationids=\"CR20 CR21 CR22 CR23\" citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e\u003c/sup\u003e. Waterborne polyurethane (WPU) emerges as a prime candidate attributable to its minimal toxicity, biodegradability, and modifiable mechanical characteristics\u003csup\u003e\u003cspan additionalcitationids=\"CR26\" citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e\u003c/sup\u003e. Notably, its intrinsic self-emulsifying nature diminishes the necessity for substantial emulsifiers or supplementary surfactants\u003csup\u003e\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e, \u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e\u003c/sup\u003e. The interfacial polymerization methodology, producing microcapsules via gentle and swift interfacial reactions, has progressively become a principal technique in agrochemical formulation, showcasing elevated encapsulation efficiency, superior thermal performance, and outstanding sustained-release characteristics\u003csup\u003e\u003cspan additionalcitationids=\"CR31 CR32\" citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003eMicroencapsulation enables spatiotemporally targeted pesticide delivery by leveraging dynamic supramolecular cross-linking networks and stimuli-triggered degradation pathways\u003csup\u003e\u003cspan additionalcitationids=\"CR35\" citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e\u003c/sup\u003e. Illustratively, Zheng et al. (2019) engineered polylactic acid-enhanced polyurethane microcapsules through interfacial polymerization, substituting eco-compatible solvents for toxic xylene. This system yielded elevated chlorpyrifos entrapment (71.0% w/w) with extended liberation spanning 65 days. The PLA-PU hybrid wall synergistically promoted payload release via coupled diffusion-degradation processes, establishing a scalable platform for sustainable insecticide regulation\u003csup\u003e\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e\u003c/sup\u003e. Comparatively, Xu et al. (2024) synthesized foliar-adherent polyurethane microcapsules (Pro@CS-OP-10) from plant-derived materials, achieving 96.38% encapsulation efficiency with enhanced light stability. The sustained-release profile extended antifungal efficacy against Fusarium graminearum in wheat crops while mitigating acute zebrafish toxicity, pioneering an ecological fungicide design\u003csup\u003e\u003cspan citationid=\"CR38\" class=\"CitationRef\"\u003e38\u003c/span\u003e\u003c/sup\u003e. Separately, Murtaza et al. implemented emulsion extrusion microencapsulation to functionalize polyester-cotton textiles with bioactive essences (limonene, camphor, linalool, menthol, 1-octanol). Validation via GC-MS, FT-IR, and SEM confirmed formulation integrity, where menthol exhibited peak repellency (97% initial efficacy, \u0026gt;\u0026thinsp;89% retention at 50 days), advancing eco-conscious durable mosquito-repellent fabric engineering\u003csup\u003e\u003cspan citationid=\"CR39\" class=\"CitationRef\"\u003e39\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003eThis investigation centers on synthesizing bendiocarb-encapsulated polyurethane microcapsules using interfacial polymerization. The resultant microcapsules underwent detailed assessment of their morphology, particle size distribution, encapsulation efficiency, and thermal performance. Anti-mosquito textiles were subsequently manufactured by proportionally combining microcapsules, binder, and JFC penetrant. The modified fabrics were appraised for laundering endurance and sustained-release performance, thereby broadening the prospective utility of microcapsules in repellent applications. By amalgamating environmentally favorable materials with stringent process refinement, this work propels sustainable vector control approaches. These efforts are consistent with worldwide efforts to reduce pesticide residues and improve environmental safety.\u003csup\u003e\u003cspan additionalcitationids=\"CR41\" citationid=\"CR40\" class=\"CitationRef\"\u003e40\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR42\" class=\"CitationRef\"\u003e42\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e"},{"header":"2. Experimental section","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e\u003ch2\u003e2.1 Materials\u003c/h2\u003e\u003cp\u003eThe original drug of bendiocarb was purchased from Saefu (Henan) Agrochemical Co., Ltd. Sodium dodecyl sulfate (SDS), isophorone diisocyanate (IPDI) and ethyl acetate were purchased from Shanghai Sinopharm Chemical Reagent Co., Ltd. Polyethylene glycol (PEG400), 1,4-butanediol (BDO) and polyvinyl alcohol (PVA, 1788) were purchased from Shanghai Titan Technology Co., Ltd.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec4\" class=\"Section2\"\u003e\u003ch2\u003e2.2 Preparation of polyurethane bendiocarb microcapsules\u003c/h2\u003e\u003cp\u003eDissolve 4.68 g of bendiocarb in 23.5 g of ethyl acetate (bendiocarb/ethyl acetate mass ratio\u0026thinsp;\u0026asymp;\u0026thinsp;1:5). Mix thoroughly and add 4.46 g of IPDI. Stir well at 25\u0026deg;C to form the oil phase. Separately, disperse 0.47 g of SDS in a 2% (w/v) PVA solution. Add 4 g of PEG400 and stir well at 25\u0026deg;C to form the aqueous phase. Add the oil phase to the aqueous phase using a homogenizer. Emulsify by high-speed stirring to form a uniform oil-in-water (O/W) emulsion. Transfer the O/W emulsion to a three-necked flask. Add 0.03 g of dibutyltin dilaurate and stir at 50\u0026deg;C (500 rpm) for 2 h. Add 0.91 g of BDO dropwise to the emulsion and continue stirring at 50\u0026deg;C (500 rpm) for an additional 2 h to facilitate microencapsulation. Centrifuge the mixture, dry the product, and isolate the polyurethane bendiocarb microcapsules. Figure\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e shows a schematic diagram of the polyurethane bendiocarb microcapsule preparation process.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec5\" class=\"Section2\"\u003e\u003ch2\u003e2.3 Characterization\u003c/h2\u003e\u003cdiv id=\"Sec6\" class=\"Section3\"\u003e\u003ch2\u003e2.3.1 Encapsulation efficiency\u003c/h2\u003e\u003cp\u003eMicrocapsule encapsulation efficiency (EE) was quantified employing high-performance liquid chromatography (HPLC). The protocol encompassed:\u003c/p\u003e\u003cp\u003e1. Quantification of Unencapsulated Bendiocarb:\u003c/p\u003e\u003cp\u003e0.1 g of microcapsule suspension was centrifuged at elevated speed (e.g., 12,000 rpm, 10 min). The microcapsules formed a pellet, leaving unbound bendiocarb within the supernatant, diluted using 100 ml of acetonitrile, and the chromatographic peak area corresponding to free bendiocarb (A₁) was ascertained directly via HPLC.\u003c/p\u003e\u003cp\u003e(2) Determination of total core material:\u003c/p\u003e\u003cp\u003eAnother equal amount of microcapsule suspension was taken, and solvents (e.g., DMSO, THF, acetone) to dissolve the polyurethane shell were added, and ultrasonication was performed for 30 min to rupture the microcapsules and release the encapsulated nuclei. The shell fragments were then removed by centrifugation (12,000 rpm for 10 min), and the supernatant was taken and diluted with 100 ml of acetonitrile to determine the total core peak area (A₂) of Bendiocarb in the sample by liquid chromatography.\u003c/p\u003e\u003cp\u003eThe encapsulation efficiency was calculated using the following formula:\u003cdiv id=\"Equ1\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equ1\" name=\"EquationSource\"\u003e\n$$\\:EE\\left(\\%\\right)=(1-\\frac{{A}_{1}}{{A}_{2}})\\times\\:100$$\u003c/div\u003e\u003cdiv class=\"EquationNumber\"\u003e1\u003c/div\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003ewhere \u003cem\u003eA\u003c/em\u003e\u003csub\u003e1\u003c/sub\u003e is the free bendiocarb peak area and \u003cem\u003eA\u003c/em\u003e\u003csub\u003e\u003cem\u003e2\u003c/em\u003e\u003c/sub\u003e is the total bendiocarb peak area.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec7\" class=\"Section3\"\u003e\u003ch2\u003e2.3.2 Other Characterizations\u003c/h2\u003e\u003cp\u003eThe apparent morphology of the microcapsules and microcapsule fabrics was observed using a scanning electron microscope (Hitachi Regulus 8100, Japan), and the core-shell structure of the microcapsules was observed using a transmission electron microscope (TEM, Tecnai-G20, FEI, Santa Clara, CA, USA).\u003c/p\u003e\u003cp\u003eThe uniformity of microcapsule particles was observed using a POM microscope (SBM-80I, Shanghai Weitu Optical and Electronic Technology Co., Ltd., China).\u003c/p\u003e\u003cp\u003eThe chemical structure of the microcapsules was characterized by Fourier transform infrared spectroscopy (Spectrum Two, Perkin-Elmer Inc., USA) in the wavelength range of 450 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e to 4000 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003eEnthalpy and thermal reliability of the microcapsules were measured by differential scanning calorimeter (DSC-4000, Perkin-Elmer Inc., USA). Each test was performed using a sample mass of 5\u0026thinsp;~\u0026thinsp;8 mg, in a nitrogen atmosphere, at temperatures ranging from 0\u0026deg;C to 300\u0026deg;C, using a heating and cooling rate of 10\u0026deg;C per minute. In addition, the thermal stability of the microcapsules was assessed using a thermogravimetric analyzer (TGA-4000, Perkin-Elmer Inc, USA).\u003c/p\u003e\u003cp\u003eMeasurement of the particle size distribution of microcapsules using a laser particle size analyzer (LS-POP 6, Zhuhai OMEC Instrument Co., Ltd., Guangdong, China).\u003c/p\u003e\u003cp\u003eEncapsulation efficiency, water washing resistance and Sustained release efficiency were assessed by determining bendiocarb content by high performance liquid chromatography (Agilent 1200, USA).\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\u003cdiv id=\"Sec8\" class=\"Section2\"\u003e\u003ch2\u003e2.4 Applications of Microencapsulation\u003c/h2\u003e\u003cdiv id=\"Sec9\" class=\"Section3\"\u003e\u003ch2\u003e2.4.1 Preparation of microencapsulated fabrics\u003c/h2\u003e\u003cp\u003eA 1:2 core-to-wall ratio microencapsulated suspension was used to proportionally mix the binder and JFC penetrant into a homogeneous aqueous dispersion for functional coating. The binder and JFC penetrant were mixed proportionally to form a homogeneous aqueous dispersion. Pre-cut mosquito net substrates (10 \u0026times; 10 cm) were immersed in a treatment bath for 60 minutes. Subsequently, the substrate was double-layered by means of a laboratory-scale laminator at a 100% wet pick-up rate. Finally, the microencapsulated textile composites were cured by oven drying (120\u0026deg;C, 3 min) to obtain the microencapsulated textile composites.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec10\" class=\"Section3\"\u003e\u003ch2\u003e2.4.2 Determination of water washing resistance and slow release efficiency\u003c/h2\u003e\u003cp\u003eWater Wash Resistance Testing:\u003c/p\u003e\u003cp\u003eStandard Solution Preparation: Precisely weigh 0.0300\u0026thinsp;\u0026plusmn;\u0026thinsp;0.0002 g of bendiocarb reference material into a 100-mL volumetric flask. Dilute to the mark with acetonitrile, sonicate for 10 min, allow cooling to ambient temperature, mix exhaustively, and filter.\u003c/p\u003e\u003cp\u003eSample Preparation: Position fabric specimens within 150 ml beakers. Accurately pipette 100 ml of acetonitrile into each beaker, seal, and sonicate for 30 min to extract the active component. The mean value serves as the analytical result.\u003c/p\u003e\u003cp\u003eChromatographic Determination: Under defined HPLC conditions, inject replicate sample aliquots until sequential injections exhibit\u0026thinsp;\u0026lt;\u0026thinsp;1.0% relative peak area variability. Analyze consecutively: duplicate injections of sample solution A, duplicate injections of sample solution B. Calculate the mean peak area for each sample duplicate. Determine bendiocarb content per unit area (mg/m\u0026sup2;) applying\u003cdiv id=\"Equ2\" class=\"Equation\"\u003e\u003cdiv format=\"TEX\" class=\"mathdisplay\" id=\"FileID_Equ2\" name=\"EquationSource\"\u003e\n$$\\:S=\\frac{{C}_{2}mP{V}_{2}}{{C}_{1}{V}_{2}}\\times\\:1000\u0026divide;{S}_{0}\\:$$\u003c/div\u003e\u003cdiv class=\"EquationNumber\"\u003e2\u003c/div\u003e\u003c/div\u003e\u003c/p\u003e\u003cp\u003eWhere:C\u003csub\u003e1\u003c/sub\u003e :Average of the peak area of the specimen of the tested component;\u003c/p\u003e\u003cp\u003eC\u003csub\u003e2\u003c/sub\u003e: Average value of the peak area of the tested component in the sample;\u003c/p\u003e\u003cp\u003eM: Mass of the tested component specimen, g;\u003c/p\u003e\u003cp\u003eP: the mass fraction of the tested component specimen, %;\u003c/p\u003e\u003cp\u003eV\u003csub\u003e1\u003c/sub\u003e: volume of acetonitrile added to the specimen, ml;\u003c/p\u003e\u003cp\u003eV\u003csub\u003e2\u003c/sub\u003e: volume of acetonitrile added in the specimen, ml;\u003c/p\u003e\u003c/div\u003e\u003c/div\u003e\n\u003ch3\u003e1000: Unit conversion between grams and milligrams;\u003c/h3\u003e\n\u003cp\u003eS\u003csub\u003e0\u003c/sub\u003e: area of mosquito nets in the examined specimen, m\u003csup\u003e\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e\u003cp\u003eAccording to the above test method, the anti-mosquito mosquito net samples were divided into 5 copies, the sample diagram as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e, representing water washing 0,, 5, 10, 15, 20 times, respectively, for liquid phase testing.\u003c/p\u003e\u003cp\u003eA series of microencapsulated mosquito net samples(Not from the same lot as the sample used for the water washing resistance test) were prepared using the described test method to evaluate slow-release characteristics. The samples were sealed and stored at 40\u0026deg;C under controlled conditions, then analyzed after specified durations (0, 7, 14, 21, and 28 days) as shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig3\" class=\"InternalRef\"\u003e3\u003c/span\u003e. We analyzed samples from each time point using liquid chromatography.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e"},{"header":"3. Results and Discussions","content":"\u003cdiv id=\"Sec13\" class=\"Section2\"\u003e\u003ch2\u003e3.1 Synthesis of microcapsules\u003c/h2\u003e\u003cp\u003eAs shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003e, the microcapsules with core-to-wall ratios of 1:3 to 2:1 were mostly spherical, exhibiting uniform particle size distribution, smooth surfaces, and no obvious defects (Figs.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003ea-d). Furthermore, for microcapsules with core-to-wall ratios of 1:3 to 2:1, no cracks or pores were observed; indicating good microcapsule dispersion, absence of agglomeration, and a stable microcapsule emulsification process with sufficient interfacial polymerization reactions. When the core-to-wall ratio was increased to 3:1, Fig.\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003ee shows that the surface roughness of microcapsules increased significantly, and some particles adhered, forming clusters. Figure\u0026nbsp;\u003cspan refid=\"Fig4\" class=\"InternalRef\"\u003e4\u003c/span\u003ef shows the sample with a core-to-wall ratio of 4:1, where the microcapsules were severely deformed, ruptured, or collapsed, and almost completely adhered together into a block-like structure. The particle size distribution was highly non-uniform, with rupture of capsule walls or leakage of core material observable in some areas.\u003c/p\u003e\u003cp\u003eThis phenomenon occurs because at an appropriate core-to-wall ratio (1:3\u0026thinsp;\u0026minus;\u0026thinsp;2:1), sufficient wall material effectively encapsulates the oil-phase droplets, forming a complete cross-linking network. During emulsification, high shear forces produce uniformly sized droplets, and interfacial polymerization forms a dense capsule wall. This wall inhibits deformation or adhesion during drying and resists shrinkage stress during solvent evaporation, thereby maintaining the spherical morphology. However, at high core-to-wall ratios, the wall material cannot completely cover the larger oil-phase droplets, leading to partial exposure of the core material at the interface. This exposure causes collapse or fusion of microcapsules due to solvent evaporation during drying. Additionally, insufficient wall material may leave unreacted isocyanate groups (-NCO), which trigger chemical cross-linking between microcapsules and aggravate adhesion.\u003c/p\u003e\n\u003cp\u003eFigure \u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003ea shows the optical micrograph of polyurethane bendiocarb microcapsules (core-to-wall ratio 1:1), revealing the spherical core-shell structure of the microcapsules. However, due to the limitations of optical microscopy in resolving nanoscale features, TEM observation is necessary. Figures\u0026nbsp;\u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003eb, \u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003ec, and \u003cspan refid=\"Fig5\" class=\"InternalRef\"\u003e5\u003c/span\u003ed show TEM images of polyurethane bendiocarb microcapsules (core-to-wall ratio 1:1). These images clearly reveal the core-shell structure of the microcapsules, with bendiocarb forming the central dark region and polyurethane forming the surrounding bright region as the wall material, confirming the successful preparation of polyurethane-coated bendiocarb microcapsules.\u003c/p\u003e\u003cdiv id=\"Sec15\" class=\"Section2\"\u003e\u003ch2\u003e3.2 Structural analysis of microcapsules\u003c/h2\u003e\u003cp\u003eThe functional group structures of both the polyurethane bendiocarb microcapsules and pure bendiocarb were analyzed using Fourier transform infrared (FTIR) spectroscopy and the IR spectra is shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig6\" class=\"InternalRef\"\u003e6\u003c/span\u003e. The results showed that the telescopic vibration absorption peak of N-H in bendiocarb was at 3370.9 cm⁻\u0026sup1;. The peak at 2945.9 cm⁻\u0026sup1; is the C-H vibration on the benzene ring of bendiocarb, and several sharp peaks appeared. The peak at 1723.4 cm⁻\u0026sup1; is the superposition peak of C\u0026thinsp;=\u0026thinsp;O in the capsule wall (polyurethane) and bendiocarb, while at 1555.1 cm⁻\u0026sup1; is the vibration peak of the benzene ring skeleton in bendiocarb, and at 1237.4 cm⁻\u0026sup1; is the vibration peak of C-O-C in the capsule wall. The region 1100\u0026ndash;1150 cm⁻\u0026sup1; contains the PEG400 C-O-C peak. The strong peak at 790 cm⁻\u0026sup1; corresponds to bendiocarb adjacent to the substituted benzene ring. There is no residual -NCO peak at 2270 cm⁻\u0026sup1; which confirms the reaction's completion. Urethane (1725 cm⁻\u0026sup1;), PEG soft segment (1100\u0026ndash;1150 cm⁻\u0026sup1;), and complete BDO chain expansion (no -OH peaks) indicate the success of vesicle wall synthesis. 790 cm⁻\u0026sup1; (neighboring substituted benzene ring) and 1450\u0026ndash;1600 cm⁻\u0026sup1; (benzene ring backbone) clearly indicate that bendiocarb is encapsulated. No peaks appear at 2270 cm⁻\u0026sup1; (confirming complete IPDI reaction) and no bendiocarb decomposition peaks (e.g., broad O-H peaks) appear. All these characteristic peaks appear simultaneously in the IR spectra of the microcapsules.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec16\" class=\"Section2\"\u003e\u003ch2\u003e3.3 Thermal properties of microcapsules\u003c/h2\u003e\u003cp\u003eFigure \u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e compares the DSC curves of polyurethane bendiocarb microcapsules and pure bendiocarb. Pure bendiocarb (Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e-a) exhibited a sharp endothermic peak at 134.1\u0026deg;C (Fig.\u0026nbsp;\u003cspan refid=\"Fig7\" class=\"InternalRef\"\u003e7\u003c/span\u003e-b), characteristic of its melting point. The peak's symmetry and lack of shoulders indicated high crystalline purity. In contrast, the microencapsulated sample showed a broader, weaker melting peak at 128\u0026deg;C, a 6.1\u0026deg;C depression. This shift arises because bendiocarb confinement within the polyurethane matrix restricts molecular mobility, hindering regular crystal formation and promoting partial or complete amorphization. Additionally, potential H-bonding between bendiocarb's carbonyl groups (C\u0026thinsp;=\u0026thinsp;O) and the polyurethane's urethane linkages (-NHCOO-), alongside hydrophobic interactions, further limits molecular motion. These interactions reduce the melting entropy of bendiocarb, consequently lowering its melting point.\u003c/p\u003e\u003cp\u003eThe thermogravimetric analysis in Fig.\u0026nbsp;8 shows that the thermal decomposition behavior of the microcapsules is tightly regulated by the core-to-wall ratio: the onset decomposition temperature (T₀) of the pure polyurethane wall is 175\u0026deg;C (complete decomposition by 450\u0026deg;C), while that of the bendiocarb feedstock is 145\u0026deg;C (complete decomposition by 240\u0026deg;C). In contrast, microcapsules with core-to-wall ratios of 1:3 to 2:1 stabilized at ~\u0026thinsp;163\u0026deg;C (18\u0026deg;C higher than the feedstock) and exhibited two-stage decomposition: core weight loss at 148\u0026ndash;240\u0026deg;C and wall weight loss at 240\u0026ndash;450\u0026deg;C. This results from the dense cross-linked network of the wall material forming a heat-shielding layer that protects the core and increases the activation energy for core decomposition. However, when the core-to-wall ratio increased to 3:1\u0026ndash;4:1, T₀ plunged to 132\u0026deg;C (the 3:1 group approached the feedstock's 145\u0026deg;C), with the decomposition curve degenerating into single-phase rapid weight loss (\u0026gt;\u0026thinsp;80% loss at 132\u0026ndash;240\u0026deg;C). This is attributed to wall material discontinuity triggering a thermal channeling effect that significantly reduces heat-shielding efficiency. Therefore, at core-to-wall ratios\u0026thinsp;\u0026le;\u0026thinsp;2:1, the wall effectively protects the core via dual mechanisms of physical isolation and heat dissipation (T₀ \u0026ge; 163\u0026deg;C), whereas at ratios\u0026thinsp;\u0026gt;\u0026thinsp;2:1, wall defects cause collapse of the protective effect (T₀ \u0026le; 145\u0026deg;C). This 2:1 threshold establishes a critical design boundary for heat-resistant microcapsules.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec17\" class=\"Section2\"\u003e\u003ch2\u003e3.4 Particle size and encapsulation efficiency\u003c/h2\u003e\u003cp\u003eThe encapsulation efficiency and particle size of microcapsules are 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\u003eThe encapsulation efficiency of microencapsulated samples with different core-to-wall ratio concentrations and particle size.\u003c/p\u003e\u003c/div\u003e\u003c/caption\u003e\u003ccolgroup cols=\"5\"\u003e\u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e\u003cdiv align=\"char\" char=\".\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e\u003cthead\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003eSample\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003eA\u003csub\u003e1\u003c/sub\u003e\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003eA\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003eEE(%)\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003eParticle size (\u0026micro;m)\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003e1:3\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003e41429\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003e311895\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003e87\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003e1.37\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003ctr\u003e\u003cth align=\"left\" colname=\"c1\"\u003e\u003cp\u003e1:2\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c2\"\u003e\u003cp\u003e22390\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c3\"\u003e\u003cp\u003e368326\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c4\"\u003e\u003cp\u003e94\u003c/p\u003e\u003c/th\u003e\u003cth align=\"left\" colname=\"c5\"\u003e\u003cp\u003e1.43\u003c/p\u003e\u003c/th\u003e\u003c/tr\u003e\u003c/thead\u003e\u003ctbody\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003e1:1\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e\u003cb\u003e29557\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e\u003cb\u003e427627\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e\u003cb\u003e93\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e\u003cb\u003e1.57\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003e2:1\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e\u003cb\u003e72606\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e\u003cb\u003e445998\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e\u003cb\u003e84\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e\u003cb\u003e1.86\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003e3:1\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e\u003cb\u003e100206\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e\u003cb\u003e498872\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e\u003cb\u003e80\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e\u003cb\u003e2.11\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003c/tr\u003e\u003ctr\u003e\u003ctd align=\"left\" colname=\"c1\"\u003e\u003cp\u003e\u003cb\u003e4:1\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e\u003cp\u003e\u003cb\u003e128453\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e\u003cp\u003e\u003cb\u003e557624\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e\u003cp\u003e\u003cb\u003e77\u003c/b\u003e\u003c/p\u003e\u003c/td\u003e\u003ctd align=\"char\" char=\".\" colname=\"c5\"\u003e\u003cp\u003e\u003cb\u003e2.32\u003c/b\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\u003eThe particle size distribution is shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig8\" class=\"InternalRef\"\u003e9\u003c/span\u003e. It can be seen that the diameter of the microcapsules is about 1\u0026ndash;3 \u0026micro;m, and the particle size of the microcapsule samples does not differ significantly. However, with increasing core-shell ratio, the particle size tends to increase. This may be attributed to the fact that higher core-shell ratios increase the proportion of core material in the oil phase while decreasing the relative content of wall monomers. Under fixed emulsification conditions (e.g., shear rate, emulsifier concentration, etc.), an increased oil-phase volume leads to larger droplets in the O/W emulsion and reduces the total amount of wall monomers. This results in decreased crosslinked network density, reduced elastic modulus of the capsule wall during curing, and greater expansion likelihood due to internal solvent (ethyl acetate) volatilization or thermal expansion, ultimately forming larger microcapsules.\u003c/p\u003e\u003cp\u003eAs shown in Fig.\u0026nbsp;\u003cspan refid=\"Fig9\" class=\"InternalRef\"\u003e10\u003c/span\u003e, the encapsulation efficiency exhibits a non-monotonic trend, initially increasing then decreasing as the core-to-wall ratio increases. This result suggests that an optimal core-to-wall ratio range (1:2\u0026thinsp;\u0026minus;\u0026thinsp;1:1) maximizes encapsulation. At low core-to-wall ratios, higher wall material content increases crosslinking density, forming dense capsule walls with high mechanical strength that effectively prevent core leakage. However, the lower oil-phase viscosity facilitates formation of small droplets under high-shear emulsification. These droplets possess large surface areas, requiring wall material to cover more interfaces, which may cause localized thinning or defects in the capsule wall. At optimal core-to-wall ratios (1:2\u0026thinsp;\u0026minus;\u0026thinsp;1:1), moderate oil-phase volume increases bendiocarb solubility in ethyl acetate toward saturation, reducing precipitation risk. Sufficient wall material volume enables formation of intact capsule walls, while highly stable emulsified droplets increase encapsulation beyond 90%. At high core-to-wall ratios (above 2:1), excessive oil-phase volume may exceed the solvent's solubility limit for bendiocarb, causing core precipitation during emulsification or curing. This forms surface adsorption or defects while insufficient wall material prevents complete capsule wall formation. Reduced crosslinking density in the capsule wall increases susceptibility to rupture or leakage, significantly decreasing encapsulation rate.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec18\" class=\"Section2\"\u003e\u003ch2\u003e3.5 Microencapsulation of finished fabrics\u003c/h2\u003e\u003cp\u003eSEM analysis (Figure.11) depicts a mosquito net fabric treated with microcapsules (core-to-wall ratio 1:2). The SEM micrograph reveals the distribution and adhesion characteristics of the capsules on the fiber substrate. Visual inspection confirms successful attachment of most microcapsules to the fiber surfaces, demonstrating effective functionalization. Furthermore, the adhered capsules exhibit a relatively uniform dispersion pattern across the fibers. This consistent distribution, avoiding localized aggregation or scarcity, indicates a well-regulated preparation process. Such process control supports stable, sustained active ingredient release in the final product. These findings validate that the microcapsules possess appropriate dimensions for fabric finishing applications.\u003c/p\u003e\u003cp\u003e\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec19\" class=\"Section2\"\u003e\u003ch2\u003e3.6 Washing Resistance\u003c/h2\u003e\u003cp\u003eSupplementary Figure \u003cspan refid=\"MOESM1\" class=\"InternalRef\"\u003eS1\u003c/span\u003e and Table \u003cspan refid=\"MOESM1\" class=\"InternalRef\"\u003eS1\u003c/span\u003e show the wash resistance of microcapsules and residual bendiocarb content in fabric after repeated laundering. Figure\u0026nbsp;\u003cspan refid=\"Fig11\" class=\"InternalRef\"\u003e12\u003c/span\u003e quantifies bendiocarb retention and loss rates post-washing. Initial drug loading (0 washes) measured 127.964 mg/m\u0026sup2;. The fabric samples experienced 47% and 70% bendiocarb loss after 5 and 10 washes, respectively, attributed primarily to rapid depletion of surface-adsorbed drug and leakage through defective capsule walls. Post-10 washes, residual drug decline markedly slowed, with merely 10.6% additional reduction after 20 washes. This stabilization confirms enhanced wash resistance, as intact microcapsule walls effectively restricted core material release. The fabric still retained 27.0% of the initial amount of drug after 20 washes, indicating that the fabric could withstand more than 20 washing cycles, which showed that the microcapsules had a certain long-lasting water washing resistance.\u003c/p\u003e\u003c/div\u003e\u003cdiv id=\"Sec20\" class=\"Section2\"\u003e\u003ch2\u003e3.7 Sustained Release Performance\u003c/h2\u003e\u003cp\u003eSupplementary Figure \u003cspan refid=\"MOESM2\" class=\"InternalRef\"\u003eS2\u003c/span\u003e and Table \u003cspan refid=\"MOESM2\" class=\"InternalRef\"\u003eS2\u003c/span\u003e present sustained-release testing results for bendiocarb content in fabric-bound microcapsules. Initial drug loading measured 131.51 mg/m\u0026sup2;. Figure\u0026nbsp;\u003cspan refid=\"Fig12\" class=\"InternalRef\"\u003e13\u003c/span\u003e quantifies bendiocarb retention and release rates over time. Following 7 days at 40\u0026deg;C, fabric residue declined to 113.96 mg/m\u0026sup2; (13.4% release), primarily through diffusion of surface-adsorbed drug and rapid escape via capsule wall micropores. Cumulative release progressed to 40.5% (day 14), 61.0% (day 21), and 69.2% (day 28). Release kinetics decelerated substantially during this period, with merely 8.2% additional release between days 21\u0026ndash;28, indicating approach toward diffusion equilibrium. A final retention of 30.8% of the initial loading after 28 days confirms significant sustained-release performance.\u003c/p\u003e\u003c/div\u003e"},{"header":"4. Conclusions","content":"\u003cp\u003eIn this study, PU microcapsules demonstrated efficacy as carriers for bendiocarb. Optimal spherical morphology (average particle size: 1.43 \u0026micro;m) was achieved at a 1:2 core-to-wall ratio, with 94% encapsulation efficiency. SEM/TEM and FTIR confirmed the dense cross-linked shell structure. Thermal analysis (TGA/DSC) revealed a dual-phase decomposition mechanism: the PU wall increased the onset degradation temperature of bendiocarb by 18\u0026deg;C, providing synergistic thermal protection. Microencapsulated functionalized fabrics retained 27% efficacy after 20 washes and exhibited 69.2% cumulative release over 28 days, outperforming conventional formulations. The core-to-wall ratio critically governs performance: ratios\u0026thinsp;\u0026gt;\u0026thinsp;2:1 cause rapid release due to wall defects, while ratios\u0026thinsp;\u0026le;\u0026thinsp;1:1 ensure structural integrity. This technology establishes a green paradigm for sustained mosquito control and holds critical implications for scalable production of eco-friendly agrochemicals.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eConflicts of Interest\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare no conflict of interest.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData Availability Statement\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors confirm that the data supporting the findings of this study are available within the article. And no new data were created.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAUTHOR INFORMATION\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCorresponding Authors\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eYan Liu - College of Chemistry and Chemical Engineering, Shanghai University of Engineering Science, Shanghai 201620, China; 0000-0002-1880-2664 Email: [email protected] (Y.L.)\u003c/p\u003e\n\u003cp\u003eBinjie Xin - School of Textile and Fashion Engineering, Shanghai University of Engineering Science, Shanghai 201620, China; orcid.org/0000-0003-0683-8018; Email: [email protected]\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWulin Xia - College of Chemistry and Chemical Engineering, Shanghai University of Engineering Science, Shanghai 201620, China\u003c/p\u003e\n\u003cp\u003eHaitao Zhou - College of Chemistry and Chemical Engineering, Shanghai University of Engineering Science, Shanghai 201620, China\u003c/p\u003e\n\u003cp\u003eChao Zheng - College of Chemistry and Chemical Engineering, Shanghai University of Engineering Science, Shanghai 201620, China\u003c/p\u003e\n\u003cp\u003eWenjie Yin - College of Chemistry and Chemical Engineering, Shanghai University of Engineering Science, Shanghai 201620, China\u003c/p\u003e\n\u003cp\u003eTianhao Lu - College of Chemistry and Chemical Engineering, Shanghai University of Engineering Science, Shanghai 201620, China\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthor Contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe manuscript was completed by the first author. All authors reviewed the manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNo funding was received\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eAl-Osaimi, H. M.; Kanan, M.; Marghlani, L.; Al-Rowaili, B.; Albalawi, R.; Saad, A.; Alasmari, S.; Althobaiti, K.; Alhulaili, Z.; Alanzi, A.; Alqarni, R.; Alsofiyani, R.; Shrwani, R., A systematic review on malaria and dengue vaccines for the effective management of these mosquito borne diseases: Improving public health. Hum Vacc Immunother 2024, 20 (1), 2337985.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eLybrand, D. B.; Xu, H. Y.; Last, R. L.; Pichersky, E., How Plants Synthesize Pyrethrins: Safe and Biodegradable Insecticides. 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Acta Trop 2024, 257, 107290.\u003c/span\u003e\u003c/li\u003e\u003cli\u003e\u003cspan\u003eMir, S. A.; Dar, B. N.; Mir, M. M.; Sofi, S. A.; Shah, M. A.; Sidiq, T.; Sunooj, K. V.; Hamdani, A. M.; Khaneghah, A. M., Current strategies for the reduction of pesticide residues in food products. J Food Compos Anal 2022, 106, 104274.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":true,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"journal-of-polymer-research","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"jpol","sideBox":"Learn more about [Journal of Polymer Research](https://www.springer.com/journal/10965)","snPcode":"10965","submissionUrl":"https://www.editorialmanager.com/jpol/","title":"Journal of Polymer Research","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false},"keywords":"interfacial polymerization, bendiocarb, polyurethane microcapsules, sustained release","lastPublishedDoi":"10.21203/rs.3.rs-6821252/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6821252/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eIn this study, waterborne polyurethane (WPU) microcapsules encapsulating bendiocarb were successfully prepared by interfacial polymerization for sustainable mosquito control. A high encapsulation efficiency of 94% was achieved by systematically optimizing the emulsifier concentration (2% PVA), core-to-wall ratio (1:2), reaction temperature (50\u0026deg;C), and reaction time (6 h). Comprehensive characterization confirmed the uniform spherical morphology (particle size 1\u0026ndash;3 \u0026micro;m), core-shell structure, and thermal stability of the microcapsules. Importantly, a core-to-wall ratio threshold of 2:1 was determined: microcapsules with core-to-wall ratios\u0026thinsp;\u0026le;\u0026thinsp;2:1 have a dense cross-linked network that provides dual core protection (physical barrier\u0026thinsp;+\u0026thinsp;thermal dissipation; initial decomposition temperature T₀ \u0026ge; 163\u0026deg;C), while ratios\u0026thinsp;\u0026gt;\u0026thinsp;2:1 lead to shell discontinuities and thermal channeling (T₀ \u0026le; 145\u0026deg;C), and the protective effect of the walls on the core is lost. Long-term efficacy of the microencapsulated fabrics was demonstrated by bioassays: 27% residual drug retention after 20 washes and the drug residue after 28 days of cumulative release (at a constant temperature of 40\u0026deg;C) was 30.8%. This study establishes an ecologically sound framework for the targeted application of pesticides based on the World Health Organization guidelines on pesticide residues.\u003c/p\u003e","manuscriptTitle":"Preparation and Characterization of Polyurethane Microcapsules for Controlled Release of Bendiocarb","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-07-11 15:14:48","doi":"10.21203/rs.3.rs-6821252/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"reviewerAgreed","content":"","date":"2025-07-14T06:42:52+00:00","index":0,"fulltext":""},{"type":"reviewersInvited","content":"","date":"2025-07-09T07:12:19+00:00","index":"","fulltext":""},{"type":"editorInvited","content":"Journal of Polymer Research","date":"2025-06-28T18:56:52+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2025-06-07T04:19:41+00:00","index":"","fulltext":""},{"type":"submitted","content":"Journal of Polymer Research","date":"2025-06-06T03:05:30+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"journal-of-polymer-research","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"jpol","sideBox":"Learn more about [Journal of Polymer Research](https://www.springer.com/journal/10965)","snPcode":"10965","submissionUrl":"https://www.editorialmanager.com/jpol/","title":"Journal of Polymer Research","twitterHandle":"","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"Springer Hybrid","inReviewEnabled":true,"inReviewRevisionsEnabled":false}}],"origin":"","ownerIdentity":"067a3888-0995-4508-b230-0fa0b20ac600","owner":[],"postedDate":"July 11th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"published-in-journal","subjectAreas":[],"tags":[],"updatedAt":"2026-04-07T16:05:02+00:00","versionOfRecord":{"articleIdentity":"rs-6821252","link":"https://doi.org/10.1007/s10965-026-04758-0","journal":{"identity":"journal-of-polymer-research","isVorOnly":false,"title":"Journal of Polymer Research"},"publishedOn":"2026-03-31 15:58:55","publishedOnDateReadable":"March 31st, 2026"},"versionCreatedAt":"2025-07-11 15:14:48","video":"","vorDoi":"10.1007/s10965-026-04758-0","vorDoiUrl":"https://doi.org/10.1007/s10965-026-04758-0","workflowStages":[]},"version":"v1","identity":"rs-6821252","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6821252","identity":"rs-6821252","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}