Thermal, electrical, optical, and antimicrobial studies of PANI/Ag nanocomposites synthesized by polymerization of aniline on γ-irradiated and PVP-capped Ag colloid

Thermal, electrical, optical, and antimicrobial studies of PANI/Ag nanocomposites synthesized by polymerization of aniline on γ-irradiated and PVP-capped Ag colloid | 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 Article Thermal, electrical, optical, and antimicrobial studies of PANI/Ag nanocomposites synthesized by polymerization of aniline on γ-irradiated and PVP-capped Ag colloid Samir M.M. Morsi, Rajia Mohsen, Hazem El-Sherif, Noha Deghiedy, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-4007882/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract A simple and new way was used to modify the thermal, electrical, optical, and antimicrobial properties of conductive polyaniline by embedding a nanosized metallic material in the polymeric matrix. The sequence of fabrication was as follows: first, preparing a silver colloid by gamma-irradiating the precursor and then, aniline monomer was polymerized in the colloid using different molarities of the dopant and the silver itself. The mentioned properties of Ag colloid and the conductive polymer / Ag nanocomposites (NCs) were studied using TGA, electrical measurements, UV-Vis spectroscopy, FTIR, TEM, SEM, DLS, SAED, and EDX. The particle size distribution of the Ag colloid is ranged from 7 to 17 nm. The results showed an increase in the D.C conductivity of NCs thin films with increasing of dopant. All the prepared NCs exhibited medium to high antibacterial activity against Escherichia coli and Staphylococcus aureus reaching the maximum efficiency at PANI: Ag: dopant molar ratio of 1:1:0.83. Also, an electrostatic interaction has been generated between the conductive PANI chains and the free electrons around Ag NPs leading to a conjugating electron cloud in the produced NCs. This electronic behavior facilitates the use of the prepared NCs as supercapacitors, sensors, photocatalysts, or antibacterial materials. Physical sciences/Chemistry Physical sciences/Materials science nanocomposite conductive polymer silver colloid polyaniline antimicrobial properties 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 Introduction Due to their capacity to endure strong electric fields with little conduction, polymers are typically regarded as electrical insulators [ 1 ]. Such insulating characteristics result from the large energy gap between the localized valence electron states and the conduction band. However, Conductive polymers such as polyaniline, polyacetylene, polypyrrole, polythiophene, etc, are considered an exceptional class of polymers. Their high conductivity, which ranges between 10 − 5 S/cm and 10 − 2 S/cm, is caused by the fact that after doping, they develop a conjugated double-bond chain structure. As a result, they can be identified by their electroactivity, environmental stability, and antibacterial activity [ 2 – 4 ]. Making polymer structures with conductive properties is a cutting-edge development [ 5 ]. This can be done by fabricating polymer composites or nanocomposites that combine the beneficial qualities of the polymer matrix and the distributed conductive fillers. The polymer matrix can either be nonconductive [ 6 ] or conductive [ 7 – 9 ]. Yet a variety of conductive fillers, including metals [ 10 , 11 ], metal oxides [ 9 ], graphite, carbon black [ 12 ], silica [ 13 ], and multiwall carbon tubes (MWCNTs) [ 6 , 14 ] may be employed. Silane coupling agent may be used for binding between polymer matrix and fillers [ 15 ]. All of these variables have an impact on the characteristics of CPNCs, including particle size, shape, and orientation as well as the concentration of polymer matrix or fillers [ 16 ]. PANI stands out from other CPs in that both charge transfer doping and protonation can be used to reversibly change its electrical properties, making it a valuable material for uses in microelectronic devices, chemical and biological sensors, actuators, and more [ 4 , 7 , 9 ]. Moreover, its backbone structure contains secondary and tertiary amines that can bind metal ions and release them when submerged in a solution with a low pH. It can be synthesized chemically, electrochemically, photochemically, and by vapor-phase or enzyme-catalyzed polymerization where each technique has its own benefits [ 17 ]. Using the chemical method, PANI can easily be made in large amounts and in powder form which is problematic in the electrochemical method [ 18 ]. Beside the attractive electrical properties of metallic NPs and its NCs, they also possess promising antibacterial properties. Ag NPs is considered the most superior metallic filler and its CPNCs occupied advanced position due to its excellent electrical properties and outstanding antibacterial properties [ 2 , 7 , 8 ]. Ag atoms can kill a variety of bacteria, viruses, and fungi by attaching to their cell walls, which lowers their permeability and inhibits cellular respiration by reducing their solubility in aqueous media. Depending on the intended use, Ag NPs can be produced simply and in a variety of ways including chemical, physical, and biological preparations [ 12 , 19 ]. Gamma-irradiation is an important physical method for their preparation [ 20 , 21 ]. Polyvinylpyrrolidone (PVP) is used as stabilizer, reducing agent, and capping agent [ 22 ]. The role of PVP in the formation of Ag NPs can be further recognized as it is a homopolymer whose repeated units contain a polar amide group that confers hydrophobic properties, as well as non-polar methylene groups conferring hydrophobic properties. In general, there are three steps to the PVP protection mechanism. A coordination bond between the stabilizer and the silver ions is formed during the initial stage. Secondly, primary nanoparticles, which are aggregation of silver atoms, are formed. Lastly, secondary Ag NPs are produced when primary Ag NPs interact with PVP or fuse together to form larger aggregates [ 19 – 22 ]. Huang et al [ 23 ] prepared PANI/Ag NC by dissolving AgNO 3 and aniline in HNO 3 solution. The solution was then deaerated by purging with N 2 and subjected to gamma-ray irradiation. In this article, the thermal, electrical, optical, and antimicrobial properties of PANI were altered by the embedding of Ag particles primarily at the nanoscale to improve its sensing and catalytic capabilities. The novelty stems from the sequence of fabrication of the nanocomposites where a silver colloid was firstly prepared by gamma-irradiation of the precursor and using PVP as a capping agent, and then polymerizing aniline monomer in the colloid using different molarities of the dopant and the silver itself. We assume that this sequential approach makes it simple to prepare the NCs while also maintaining their purity. Ag NPs were prepared separately by gamma-ray irradiation and away from the chemical reducing agents. Then, PANI was prepared, in situ of colloidal Ag, in bulk amount and powder form taking advantage of the simple chemical redox polymerization method. Materials and Methods Materials Aniline monomer, ammonium persulfate (APS) 98% initiator, hydrochloric acid 35–38% doping agent, and polyvinyl pyrrolidone (PVP) (MWt 100,000) capping agent were obtained from Merck, Fischer Laboratory Reagent, Fisher Scientific, BIO Basic Canada Inc, respectively. Silver nitrate (AgNO 3 ) was obtained from Sisco Research Laboratories PVT. Ltd. India. Methodology • Synthesis of Silver colloid Silver nanoparticles colloid was synthesized following the procedure described Afify et al [ 21 ]. In 100 ml distilled water, 1.7 g of silver nitrate and 0.034 g of PVP were dissolved to prepare the AgNO 3 solution. Gamma-irradiation was applied to the solution at a dose of 50 KGy by using a Co-60 -cell-220 source. A colloidal solution of silver nanoparticles suspended in water was obtained. • Synthesize polyaniline/silver nanocomposites The formed colloid was used to as a medium for the polymerization of aniline to synthesize polyaniline/silver nanocomposites (PANI/Ag NCs). The polymerization was carried out by chemical oxidative reaction in the presence of APS as an initiator and HCl as a dopping agent. The molar ratio of aniline was fixed at 1, while that of both Ag and HCl varied at 0.11 to 1 and 0.83 to 2.5, respectively, as shown in Table 1 . Aniline was added to the Ag NPs colloid and HCl was added to the mixture with continuous stirring at room temperature for 30 min. An initiator solution was prepared by dissolving APS in distilled water. The initiator solution was drop-wise poured into the mixture to initiate the polymerization reaction with continuous stirring for 12 hours. PANI/Ag NCs were precipitated as dark green powders, which were filtrated, washed, and dried at room temperature. Characterization techniques The particle size distribution was determined by dynamic light scattering (DLS) in the range of 0.4–10,000 nm using Malvern Zetasizer Nano, UK. UV-Vis absorption spectra were performed on Agilent Cary 60 UV-Vis Spectrophotometer. X-ray diffraction (XRD) was used to analyze the samples using Philips PW 1830 diffractometer with CuK (= 0.154 nm) radiation source operated at 35 mA and 40 kV. The particle size of Ag NPs was calculated using Debye–Scherrer’s equation (D = 0.92 λ/β cos θ), where, 0.92 is a constant, λ is the wavelength of the X-rays and β is the full width at half maximum (FWHM) of the diffraction peaks and θ the corresponding diffraction angle in radian. Fourier transform infrared (FTIR) spectra were recorded by JASCO FTIR 6100 in the range of 4000–400 cm -1 with 4 cm -1 resolution and 50 scans with a scanning speed of 2 mm/s. TEM images were carried out by high-resolution JEOL-2100 TEM. Additionally, HR-TEM was used to analyze the silver colloid by selected area electron diffraction (SAED). Scanning micrographs were performed on Quantum Field Emission Gun 250 with Energy disperses x-rays analysis (EDX) by Ametek Holland. Shimadzu TGA-50 thermogravimetric analyzer was used to perform the thermogravimetric analysis (TGA), Columbia, EUA, under a nitrogen atmosphere at 10°C/min heating rate from room temperature to 600°C. Thin films of the NCs powder having thickness 0.5 mm were fabricated by compression molding in a hydraulic press at 170 o C and under pressure of 100 pounds/in 2 . The D.C. electrical conductivities of the thin films were measured by Hioki 3522-50 LCR Hi Tester (Japan). Antibacterial and antifungal activities toward ( Escherichia coli G - and Staphylococcus aureus G + ) and ( Asprigillus flavus and Candida albicans ) were determined using modified Kirby- Bauer disc diffusion by Hioki 3522-50 LCR Hitester (Japan). Mueller–Hinton agar is used for determination of susceptibility of microorganisms to antimicrobial agents. Results and discussion Formation and characterization of colloidal Ag NPs A schematic illustration of the synthesis of Ag NPs via gamma-irradiation is shown in Fig. 1. Water molecules are radiolyzed when silver nitrate solution is exposed to γ-rays. In turn, this reaction releases hydrogen atoms (H*) and hydrated electrons (e-). The latter species are capable of reducing Ag cations (Ag+) to Ag atoms (Ag o ). Clusters of Ag NPs are formed as the silver nuclei grow. In order to ensure the growth and stability of the Ag NPs, PVP is used to prevent the cluster aggregation by capping on their surfaces. The UV-Vis absorption spectrum of the synthesized Ag NPs is shown in Fig. 2a. Around 428 nm, the distinctive Ag peak is plainly visible as a broad absorption band. The combined vibration of the free electrons on Ag NPs in resonance with the incident light causes this band to arise. The lack of any other peaks in the spectrum beside the Ag peak confirms their purity. The FTIR spectrum of Ag NPs is presented in Fig. 2b. The bands at 1668 cm -1 and 1041 cm -1 are characteristic to the amide group C = O stretching and C-N stretching of PVP. The existence of a peak at around 1382 cm -1 may be related to N-O stretching of the precursor AgNO 3 . However, the characteristic band of Ag NPs appeared at 552 cm -1 . From XRD pattern (Fig. 2c) and in agreement with silver JCPDS File No. 04-0783 from ASTM, the Face Centered Cubic silver crystals of the crystallographic planes 111, 200, 220, 311, and 222 appeared at 2θ of 38.2°, 44.8°, 64.4°, 77.5°, and 81.4°. There were no discernible extra phases found in the XRD pattern. This displays the purity of the generated Ag NPs. The highly crystalline structure was highlighted by the sharpness of the peaks. The average particle size was determined using the main diffraction peak (111) to be 15.58 nm. The DLS graph of the prepared Ag NPs colloid is shown in Fig. 2d. The distribution sizes in the figure are extremely narrow, ranging from 7 nm to 17 nm. The scale is located in the nano size and the colloid's average particle size is 11 nm. The SEM micrograph and TEM image of the Ag NPs (Fig. 3a and Fig. 3b, respectively) showed aggregated spherical particles of 8 to 10 nm size which lies within the particle size distribution of DLS analysis. The elemental composition of Ag NPs by EDX analysis (Fig. 3c) revealed pure signals from the silver atoms. Four signal energy peaks, characteristic to Ag atoms and demonstrating the pure crystalline nature of the Ag colloid, appeared at 2.76 KeV, 3 KeV, and 3.16 and 3.35 KeV which are associated with the emission of M-shell, L α -shell, and L β -shell electrons from silver atoms, respectively. Figure 3d displays the SAED pattern of the Ag colloid. The image shows circular rings that reflect the crystalline nature of the silver particles, which represent the (111), (200), (220), (311), (222) and (420) planes. These levels match with fcc of silver (JCPDS 04-0783). Characterization of PANI/Ag NCs FTIR spectra of PANI/Ag NCs are shown in Fig. 4. The characteristic bands of PANI are well observed in the spectra at 3467 − 3436 and 1163 − 1132 cm − 1 which assigned to N-H stretching, and C-N stretching, respectively. These two bands are shifted to lower wavenumbers with increasing the amount of Ag NPs in the NCs. This may be due to the interaction between the nitrogen atoms forming the stretched-bonds and Ag NPs. This interaction weakens the N-H and C-N bonds resulting their stretching at lower wavenumbers. C = C stretching of quinoid and benzenoid rings appeared between 1365 cm − 1 to 1583 cm − 1 . The band at 2354 cm − 1 may be related to conjugated = C-C = N stretching and the C-H aliphatic symmetric and asymmetric stretching bands are emerged at 2930 and 2863 cm − 1 , respectively. The band at 1684 cm − 1 to 1652 may be related to PVP stabilizer used in the preparation of Ag colloid and C = N stretching of PANI. The shift to lower wavenumbers from NC1 to NC4 in this band proves the physical and electrostatic interactions between Ag NPs and PANI chains. The EDX analysis of PANI, NC1, NC2, NC3, and NC4 are shown in Fig. 5. The major elements appeared in the EDX spectrum of PANI are carbon, nitrogen, oxygen, and chlorine. However, three signal energy peaks appeared at 3.02 keV, 3.30 keV and 3.56 keV in NCs spectra which are associated with the emission of L-shell electrons from silver atoms. The intensity of these peaks increased with increasing the amount of Ag NPs in the NCs and the weight % rose from 16.37% in NC1 to 51.13% in NC4. Whereas, the intensity of peaks at 0.23 KeV (C K-shell), 0.36 KeV (N K-shell), 0.49 KeV (O K-shell), and 2.62 KeV (Cl K-shell) decreased and their weight % declined with increasing amount of Ag NPs in the NCs. All these results indicate the success of the aniline polymerization process on the surface of the Ag NPs in the colloid. Figure 6 demonstrates the SEM micrographs of NC1, NC2, NC3, and NC4. Images of NC1 (Fig. 6a) and NC2 (Fig. 6b) show flaky sheets of PANI with some distributed rod-like structures. Additionally, in NC1, the polymer seemed to entirely encase the Ag particles, whereas in NC2, they were just faintly visible alone. In NC3, these particles distributed throughout the polymer matrix, while in NC4 Ag NPs appeared as agglomerates. The DLS curves of PANI, NC1, NC2, NC3, and NC4 are presented in Fig. 7. PANI particles range in size from 45 nm to 71 nm, with the majority being 58 nm. Whereas, with the polymerization of aniline in the presence of the least quantity of silver, the strength and amplitude of the PANI peak declined, and a new peak with a narrower size range formed. This new peak, which varies in size from 36 nm to 50 nm with the majority at 42 nm, demonstrates the deposition of PANI layers on the Ag particles and generation of the core-shell NC1. The DLS curve of NC2 resembles that of NC1, with the PANI peak having less intensity and width and the NC peak having a stronger and wider size range. This is due to the fact that more amount of aniline polymerized on the surface of the Ag particles, which increased its amount in NC2 than NC1. As a result, less pure PANI was produced, and a shift to lower size could be seen. The absence of Ag peak implies that PANI has completely encapsulated all of the silver's particles in both NC1 and NC2. However, as the amount of silver in the polymerization medium increased, clusters of its particles started to form, which eventually broke off from the composite and sank alone. This is evidenced by the appearance of silver peaks in both NC3 and NC4. The particle size distribution profile of the NCs is in good agreement with the SEM images, which showed aggregations of silver particles in both NC3 and NC4. The XRD patterns of NC1, NC2, NC3, and NC4 are illustrated in Fig. 8. The three distinct and broad peaks, with diffraction angles 15.4 o , 20.7 o , and 25.5 o , which correspond to crystal planes 121, 113, and 322, demonstrate the semi-crystalline nature of PANI and that these three crystal planes were the direction of most of its chains. The broadness and intensity of the peaks signify the degree of chain orientation in the plane and the population of crystallites, respectively. The detected peaks are consistent with those reported by the Joint Committee on Powder Diffraction Standards (no. 72–0634). On the other hand the diffraction angles of Ag NPs were emerged at 2θ of 38.2°, 44.6°, 64.8°, 77.3°, and 81.8°, indicating that the aniline polymerization had no effect on their crystallinity. It is evident that when the amount of Ag in the NCs rose, the intensity of the Ag peaks increased, and vice versa for PANI. Optical properties of PANI/Ag NCs UV-Vis spectroscopy was used to examine the opto-electronic characteristics of PANI and PANI/Ag NCs and their spectra are shown in Fig. 9. The UV-Vis spectrum of PANI showed three spectral maxima at 207 nm, 373 nm, and 745 nm. The former is due to the transition of the electrons in the bonding π orbital to the antibonding π* orbital. This type of π- π* transition is associated with the conjugated systems of benzenoid structure in PANI. The second electron transition at 373 nm is caused by the non-bonding pair in an n-orbital to the antibonding π* orbital. This n–π* transitions appeared in the quinonoid ring of PANI. The third broad band is ascribed to polaron/bipolaron resonance which proves that the prepared PANI is in the conductive form. However, a conjugating electron cloud is produced easily after the embedding of Ag NPs, rich in free electrons, with emeraldine salt PANI. This is induced by the presence of electrostatic interaction between PANI chains and Ag NPs which caused a large number of free electrons around Ag atoms that easily conjugate with nitrogen atoms of PANI. Therefore, a bathochromic shift in the UV-Vis spectra of the NCs is observed, where the peaks in PANI spectrum at wavelength 207 nm and 745 nm are red shifted gradually with decreasing the amount of PANI in the NC to reach 233 nm and 782 nm for NC4 associated with a hypochromic shift. The peak at 373 nm in the PANI spectrum became merged with the broad Ag peak which appeared at wavelength 432 nm. This electronic behavior of the NCs enhances their application as supercapacitors, photocatalysts, or antimicrobial agents. Thermal properties of PANI/Ag NCs TGA profiles of PANI and the prepared NCs are depicted in Fig. 10. All samples show a significant weight loss at temperatures below 100°C, which is caused by the evaporation of the absorbed water and some volatiles. This weight loss amounted to 15% for pure PANI and decrease with increasing the amount of Ag in the NCs. When the temperature reached 170°C, the dopant began to decompose until 250°C, and PANI chains were completely deprotonated. At about 370°C, the main backbone chains of PANI degraded. It is visually evident from the TGA curves that Ag NPs greatly enhanced the thermal stability of PANI where the mass loss at the deprotonation of PANI decreased from 25% (PANI) to only 12% (NC4). Also, the mass loss at the degradation of PANI reduced from 60% (PANI) to 34% (NC4). The residue at 700 o C was only 12% for PANI, whereas it reached more than 50% in NC4. Electrical properties of PANI/Ag NCs The DC conductivity results of Ag NCs are listed in Table 1 and illustrated in Fig. 11. The influence of two different factors on the electrical conductivity has been studied, namely the effect of both dopant concentration (Fig. 11a) and the silver concentration (Fig. 11b) on the nanocomposites, which reveals: With the increase of the molar ratio of HCl in the NCs from 0.83 to 2.5, the electrical conductivity increases steadily (Fig. 11a), which shows the obvious role of dopant in increasing the conductivity. The electrical conductivity results of the NCs with doping molar ratio of 2.5 showed that they can be used as excellent semiconductors. Also, good conductivity was obtained in the NCs with a dopant molarity of 0.83 when ratios of 0.11 and 0.23 mol Ag NPs were used in the NCs. This qualifies both NC1 and NC2 to be used as semiconductors. Although it was anticipated that the D.C. conductivity would increase as the molar ratio of silver in the NCs increased, it was discovered that this was not the case for either of the two doping acid ratios (Fig. 11b). This can be explained by the extraordinary surface area and energy of minute size Ag NPs led to strengthen the interaction between their particles and aggregations occurred as illustrated in SEM images (Fig. 6), while at the same time the interaction towards the PANI matrix had been weakened. Therefore, as the content of Ag NPs increased, their accumulation/agglomeration in the polymer NCs increased, and thus the electrical conductivity decreased [ 24 ]. Also, as the Ag NPs content increased, the PANI decreased such that it was not sufficient to coat efficiently Ag NPs, thus Ag NPs became susceptible to agglomeration. Accordingly, increasing the PANI content may be helpful. Table 1 Chemical composition and electrical properties of PANI/Ag nanocomposites Nanocomposite Molar ratio of PANI/Ag NCs DC (S/cm) Ag Aniline Dopant NC1 0.11 1.00 0.83 1.8 x 10 − 2 NC2 0.23 1.00 0.83 1.4 x 10 − 3 NC3 0.58 1.00 0.83 4.1 x 10 − 5 NC4 1.00 1.00 0.83 8.5 x 10 − 7 NC5 0.11 1.00 2.50 5.6 x 10 − 2 NC6 0.23 1.00 2.50 3.6 x 10 − 2 NC7 0.58 1.00 2.50 6.8 x 10 − 3 NC8 1.00 1.00 2.50 1.5 x 10 − 3 Antimicrobial properties of PANI/Ag NCs Table 2 and Fig. 12 show the antibacterial and antifungal activities of the synthesized PANI/Ag NCs. All NCs showed antibacterial effect, while some of them which contained high doses of Ag NPs showed some antifungal effect. All the prepared composites displayed high levels of bacterial resistance, which peaked when NC4 was used, as it had an effectiveness of 124% against Staphylococcus aureus and 84% against Escherichia coli . It is also clear from the results that the efficiency of the composites against bacteria increased with the increase silver content. However, the NCs showed much less resistance to fungi, such that many of them did not show any resistance, nevertheless by increasing the percentage of silver in the NCs, its efficiency increased. This indicates that the strongest factor for resisting bacteria or fungi in these composites lies in silver content. The effectiveness of silver as an antibacterial lies in its deadly effect by making holes in the cell wall of the bacterial cell, causing its destruction upon entering it. Silver ions bind to basic components of the cell such as DNA, and prevent bacteria from performing even their most basic functions. Table 2 Antibacterial and antifungal activities of PANI/Ag NCs . Sample Inhibition zone diameter ( mm / mg sample ) Escherichia coli (G − ) Staphylococcus aureus (G + ) Aspergillus flavus (Fungus) Candida Albicans (Fungus) Control : DMSO 0.0 0.0 0.0 0.0 Standard Ampicillin antibacterial agent 25 21 -- -- Amphotericin B Antifungal agent -- -- 16 19 Sample 11 % to Standard 12 % to Standard 0.0 % to Standard 0.0 % to Standard NC1 44 57 0.0 0.0 NC2 15 60 15 71.4 0.0 0.0 10 52.6 NC3 22 88 20 95 10 62.5 10 52.6 NC4 21 84 26 123.8 10 62.5 11 57.9 NC5 12 48 10 47.6 0.0 0.0 0.0 0.0 NC6 9 39 10 49.6 0.0 0.0 0.0 0.0 NC8 15 60 16 76.2 0.0 0.0 9 47.4 Values with respect to standards, below 30% is considered weak, from 30–60% and over 60% are considered medium and high, respectively. Conclusion Polyaniline / Ag nanocomposites were fabricated in sequential steps. The silver colloid was firstly prepared by gamma-irradiation of the precursor and by using PVP as a capping agent, and then aniline monomers were chemically polymerized in the silver colloid. Different molar ratios of aniline to Ag and HCl dopant to aniline were used. FTIR, UV-Visible, EDX, and XRD analysis confirmed the formation of silver nanoparticles in the colloid. The size of the spherical-shaped silver particles was ranged from 7 nm to 17 nm as illustrated from DLS, TEM, and XRD analysis. The aim of the research work was to modify the thermal, optical, electrical and antimicrobial properties of the materials used in the nanocomposites. The silver particles significantly enhanced the thermal stability of polyaniline at all stages of thermal degradation of polyaniline (as evidenced from TGA profiles). The presence of electrostatic interaction between polyaniline chains and silver nanoparticles was confirmed from the UV-Visible spectroscopy where a conjugating electron cloud was produced after the impregnation of silver nanoparticles, rich in free electrons, with emeraldine salt polyaniline. This induced a large number of free electrons around silver atoms to conjugate with the nitrogen atoms of polyaniline. The electrical conductivity increased with increasing of the dopant. Due to the minute particle size of the Ag colloid, some agglomeration of Ag NPs occurred in the nanocomposites, which increased with increasing of Ag concentration in the nanocomposites and resulting in a decrease in the electrical conductivity. The prepared nanocomposites have excellent antibacterial activity to E-Coli (Gram -) and S. aureus (Gram +) but medium activity to Candida albicans fungus. The fabricated nanocomposites can be used in food packaging applications, supercapacitors, photocatalysts, antimicrobial agents and sensors. Data availability The data are available from the corresponding author on reasonable request. [Name: Samir M.M. Morsi, e-mail: [email protected] ]. Declarations Competing interests The authors declare no competing interests. Author Contribution Samir M. M. 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Structural and morphological study of gamma-irradiation synthesized silver nanoparticles. Polymer Composites, 2017; 38: 2687–2694. Malina D, Kupiec AS, Wzorek Z, Kowalski Z. Silver nanoparticles synthesis with different concentrations of polyvinylpyrrolidone. Digest Journal of Nanomaterials and Biostructures. 2012; 7: 1527–1534. Huang Z, Shi L, Zhu Q, Zou J, Chen T. Fabrication of Polyaniline/Silver Nanocomposite Under Gamma-ray Irradiation. Chinese Journal of Chemical Physics. 2010; 23: 701–706. Ashraf MA, Peng W, Zare Y, Rhee KY. Effects of size and aggregation/agglomeration of nanoparticles on the interfacial/interphase properties and tensile strength of polymer nanocomposites, Nanoscale Research Letters. 2018; 13: 214. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. 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-4007882","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":290608509,"identity":"8c5b7f28-1cd1-4e5c-9800-ab71e7f9ddba","order_by":0,"name":"Samir M.M. Morsi","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA8ElEQVRIiWNgGAWjYJCCA0CcwMDA2MDAUAFkMjM3kKDlwBmQFkbCWhggWoDgYBuIJKBFvv104uHKHLs8frHDzZ8/zquN5m8HavlRsQ2nFoMzuRsOnt2WXCw5O7FN4uC247kzDjM2MPacuY1bCwNQS+O2A4kbbie2MRzcdiy3AaiFmbENtxb5/rcQLftvJzZ/ODjnWO58QloYbsBskU5skDjYUJO7gZAWgxtgW5ITZwAdJnHm2IHcjUAtB/H5Rb4/d/PHxm12if2z0x9/qKipy513/vDBBz8q8DgMDRwGkweIVg8EdaQoHgWjYBSMghECAPima1z2saFdAAAAAElFTkSuQmCC","orcid":"","institution":"National Research Centre","correspondingAuthor":true,"prefix":"","firstName":"Samir","middleName":"M.M.","lastName":"Morsi","suffix":""},{"id":290608512,"identity":"e1c1fd2a-2cbf-48f0-a5eb-1fe8164e5b4b","order_by":1,"name":"Rajia Mohsen","email":"","orcid":"","institution":"National Research Centre","correspondingAuthor":false,"prefix":"","firstName":"Rajia","middleName":"","lastName":"Mohsen","suffix":""},{"id":290608514,"identity":"51455c1c-6b5f-4548-98a7-da44fa5dec67","order_by":2,"name":"Hazem El-Sherif","email":"","orcid":"","institution":"National Research Centre","correspondingAuthor":false,"prefix":"","firstName":"Hazem","middleName":"","lastName":"El-Sherif","suffix":""},{"id":290608516,"identity":"69002e71-eeb1-4478-a2c7-b4488f5c720b","order_by":3,"name":"Noha Deghiedy","email":"","orcid":"","institution":"Egyptian Atomic Energy Authority","correspondingAuthor":false,"prefix":"","firstName":"Noha","middleName":"","lastName":"Deghiedy","suffix":""},{"id":290608517,"identity":"771c21e1-e346-4ecb-a1df-6fcd741de18b","order_by":4,"name":"Ahmed Ghoneim","email":"","orcid":"","institution":"National Research Centre","correspondingAuthor":false,"prefix":"","firstName":"Ahmed","middleName":"","lastName":"Ghoneim","suffix":""}],"badges":[],"createdAt":"2024-03-03 07:45:35","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-4007882/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-4007882/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":54698049,"identity":"8a18a121-ed4a-4c00-8267-6a0b0c3420f3","added_by":"auto","created_at":"2024-04-15 11:41:07","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":266249,"visible":true,"origin":"","legend":"\u003cp\u003eSynthesis of colloidal silver nanoparticles by μ γ-radiation induction.\u003c/p\u003e","description":"","filename":"1.png","url":"https://assets-eu.researchsquare.com/files/rs-4007882/v1/55f92020ea617535e3d5d6ea.png"},{"id":54697098,"identity":"38fa85ae-3567-4a37-a6c3-8a7b8ed3043a","added_by":"auto","created_at":"2024-04-15 11:33:07","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":182111,"visible":true,"origin":"","legend":"\u003cp\u003eUV-Visible absorption spectrum (a), FTIR spectrum (b), XRD pattern (c), and DLS curve (d) of Ag NPs.\u003c/p\u003e","description":"","filename":"2.png","url":"https://assets-eu.researchsquare.com/files/rs-4007882/v1/6e704f960d1103ed12565ef9.png"},{"id":54697100,"identity":"46fb20b4-a0a6-4ced-a795-87c4c5920eec","added_by":"auto","created_at":"2024-04-15 11:33:07","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":741626,"visible":true,"origin":"","legend":"\u003cp\u003eSEM micrograph (a), TEM images (b), EDX spectrum (C), and SAED pattern (d) of Ag NPs.\u003c/p\u003e","description":"","filename":"3.png","url":"https://assets-eu.researchsquare.com/files/rs-4007882/v1/cfac823bc86b904e018e06bc.png"},{"id":54697101,"identity":"34fe3b79-6bcc-4b6c-8200-94bcda4d4cf2","added_by":"auto","created_at":"2024-04-15 11:33:07","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":205235,"visible":true,"origin":"","legend":"\u003cp\u003eFTIR spectra of NC1, NC2, NC3, and NC4 nanocomposites.\u003c/p\u003e","description":"","filename":"4.png","url":"https://assets-eu.researchsquare.com/files/rs-4007882/v1/e13c9d6167db12f570cf3e86.png"},{"id":54698485,"identity":"52efe485-fad2-46ac-ae6d-598852ff5fb9","added_by":"auto","created_at":"2024-04-15 11:49:07","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":162015,"visible":true,"origin":"","legend":"\u003cp\u003eEDX spectra of PANI, NC1, NC2, NC3, and NC4.\u003c/p\u003e","description":"","filename":"5.png","url":"https://assets-eu.researchsquare.com/files/rs-4007882/v1/a8ff36da991c7443226c35a3.png"},{"id":54697106,"identity":"0a96835a-9c82-44bd-8078-fbf91279b8f3","added_by":"auto","created_at":"2024-04-15 11:33:07","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":1007754,"visible":true,"origin":"","legend":"\u003cp\u003eSEM image of (a) NC1, (b) NC2, (c) NC3, and (d) NC4.\u003c/p\u003e","description":"","filename":"6.png","url":"https://assets-eu.researchsquare.com/files/rs-4007882/v1/705acbd4e4c647649eb5c107.png"},{"id":54697110,"identity":"9a648037-888a-4ff4-9bc7-7be927c4a179","added_by":"auto","created_at":"2024-04-15 11:33:08","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":184583,"visible":true,"origin":"","legend":"\u003cp\u003eDLS profiles of PANI, NC1, NC2, NC3, and NC4.\u003c/p\u003e","description":"","filename":"7.png","url":"https://assets-eu.researchsquare.com/files/rs-4007882/v1/f21d9ffa57051408ffe2c916.png"},{"id":54697109,"identity":"94ef6cb0-04e8-4556-9b63-6c1f476ed543","added_by":"auto","created_at":"2024-04-15 11:33:08","extension":"png","order_by":8,"title":"Figure 8","display":"","copyAsset":false,"role":"figure","size":207946,"visible":true,"origin":"","legend":"\u003cp\u003eXRD patterns of NC1, NC2, NC3, and NC4.\u003c/p\u003e","description":"","filename":"8.png","url":"https://assets-eu.researchsquare.com/files/rs-4007882/v1/2fd2cd35adda40fc80a1152e.png"},{"id":54697108,"identity":"2e8aad1e-6ea8-49e4-9de3-afa0a2a72111","added_by":"auto","created_at":"2024-04-15 11:33:07","extension":"png","order_by":9,"title":"Figure 9","display":"","copyAsset":false,"role":"figure","size":204247,"visible":true,"origin":"","legend":"\u003cp\u003eUV-Vis absorption spectra of PANI, NC1, NC2, NC3, and NC4.\u003c/p\u003e","description":"","filename":"9.png","url":"https://assets-eu.researchsquare.com/files/rs-4007882/v1/e58e8f4cd06acb1af47c945f.png"},{"id":54697107,"identity":"aeb902bd-cddc-4567-a1bb-49dabadaf259","added_by":"auto","created_at":"2024-04-15 11:33:07","extension":"png","order_by":10,"title":"Figure 10","display":"","copyAsset":false,"role":"figure","size":533794,"visible":true,"origin":"","legend":"\u003cp\u003eTGA curves of PANI, NC1, NC2, NC3, and NC4.\u003c/p\u003e","description":"","filename":"10.png","url":"https://assets-eu.researchsquare.com/files/rs-4007882/v1/38f906249e5fc91face0758f.png"},{"id":54697105,"identity":"8a46fe6d-974b-4f8f-a50f-30c95c8f6722","added_by":"auto","created_at":"2024-04-15 11:33:07","extension":"png","order_by":11,"title":"Figure 11","display":"","copyAsset":false,"role":"figure","size":158128,"visible":true,"origin":"","legend":"\u003cp\u003eThe D.C electrical conductivity of PANI / Ag nanocomposite using varying dopant [a] and silver [b] molar concentrations.\u003c/p\u003e","description":"","filename":"11.png","url":"https://assets-eu.researchsquare.com/files/rs-4007882/v1/4b9ce7367c0d1ef98973f5f7.png"},{"id":54698050,"identity":"2d1c5ff9-8dc1-47da-a6ee-1dc10e7f8aea","added_by":"auto","created_at":"2024-04-15 11:41:07","extension":"png","order_by":12,"title":"Figure 12","display":"","copyAsset":false,"role":"figure","size":401001,"visible":true,"origin":"","legend":"\u003cp\u003eThe antibacterial and antifungal activities of NCs.\u003c/p\u003e","description":"","filename":"12.png","url":"https://assets-eu.researchsquare.com/files/rs-4007882/v1/1b314f888c162e0796836581.png"},{"id":56066931,"identity":"256aba51-6ac5-45e3-9b37-d7d0bc30e452","added_by":"auto","created_at":"2024-05-08 06:32:36","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":4503782,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-4007882/v1/e8a99f3a-cf7a-43ae-9b09-af52d222711e.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Thermal, electrical, optical, and antimicrobial studies of PANI/Ag nanocomposites synthesized by polymerization of aniline on γ-irradiated and PVP-capped Ag colloid","fulltext":[{"header":"Introduction","content":"\u003cp\u003eDue to their capacity to endure strong electric fields with little conduction, polymers are typically regarded as electrical insulators [\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e]. Such insulating characteristics result from the large energy gap between the localized valence electron states and the conduction band. However, Conductive polymers such as polyaniline, polyacetylene, polypyrrole, polythiophene, etc, are considered an exceptional class of polymers. Their high conductivity, which ranges between 10\u003csup\u003e\u0026minus;\u0026thinsp;5\u003c/sup\u003e S/cm and 10\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e S/cm, is caused by the fact that after doping, they develop a conjugated double-bond chain structure. As a result, they can be identified by their electroactivity, environmental stability, and antibacterial activity [\u003cspan additionalcitationids=\"CR3\" citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eMaking polymer structures with conductive properties is a cutting-edge development [\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e]. This can be done by fabricating polymer composites or nanocomposites that combine the beneficial qualities of the polymer matrix and the distributed conductive fillers. The polymer matrix can either be nonconductive [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e] or conductive [\u003cspan additionalcitationids=\"CR8\" citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. Yet a variety of conductive fillers, including metals [\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e], metal oxides [\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e], graphite, carbon black [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e], silica [\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e], and multiwall carbon tubes (MWCNTs) [\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e] may be employed. Silane coupling agent may be used for binding between polymer matrix and fillers [\u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e]. All of these variables have an impact on the characteristics of CPNCs, including particle size, shape, and orientation as well as the concentration of polymer matrix or fillers [\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e].\u003c/p\u003e \u003cp\u003ePANI stands out from other CPs in that both charge transfer doping and protonation can be used to reversibly change its electrical properties, making it a valuable material for uses in microelectronic devices, chemical and biological sensors, actuators, and more [\u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e]. Moreover, its backbone structure contains secondary and tertiary amines that can bind metal ions and release them when submerged in a solution with a low pH. It can be synthesized chemically, electrochemically, photochemically, and by vapor-phase or enzyme-catalyzed polymerization where each technique has its own benefits [\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e]. Using the chemical method, PANI can easily be made in large amounts and in powder form which is problematic in the electrochemical method [\u003cspan citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eBeside the attractive electrical properties of metallic NPs and its NCs, they also possess promising antibacterial properties. Ag NPs is considered the most superior metallic filler and its CPNCs occupied advanced position due to its excellent electrical properties and outstanding antibacterial properties [\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e]. Ag atoms can kill a variety of bacteria, viruses, and fungi by attaching to their cell walls, which lowers their permeability and inhibits cellular respiration by reducing their solubility in aqueous media. Depending on the intended use, Ag NPs can be produced simply and in a variety of ways including chemical, physical, and biological preparations [\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e, \u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. Gamma-irradiation is an important physical method for their preparation [\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e, \u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. Polyvinylpyrrolidone (PVP) is used as stabilizer, reducing agent, and capping agent [\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. The role of PVP in the formation of Ag NPs can be further recognized as it is a homopolymer whose repeated units contain a polar amide group that confers hydrophobic properties, as well as non-polar methylene groups conferring hydrophobic properties. In general, there are three steps to the PVP protection mechanism. A coordination bond between the stabilizer and the silver ions is formed during the initial stage. Secondly, primary nanoparticles, which are aggregation of silver atoms, are formed. Lastly, secondary Ag NPs are produced when primary Ag NPs interact with PVP or fuse together to form larger aggregates [\u003cspan additionalcitationids=\"CR20 CR21\" citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e]. Huang et al [\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e] prepared PANI/Ag NC by dissolving AgNO\u003csub\u003e3\u003c/sub\u003e and aniline in HNO\u003csub\u003e3\u003c/sub\u003e solution. The solution was then deaerated by purging with N\u003csub\u003e2\u003c/sub\u003e and subjected to gamma-ray irradiation.\u003c/p\u003e \u003cp\u003eIn this article, the thermal, electrical, optical, and antimicrobial properties of PANI were altered by the embedding of Ag particles primarily at the nanoscale to improve its sensing and catalytic capabilities. The novelty stems from the sequence of fabrication of the nanocomposites where a silver colloid was firstly prepared by gamma-irradiation of the precursor and using PVP as a capping agent, and then polymerizing aniline monomer in the colloid using different molarities of the dopant and the silver itself. We assume that this sequential approach makes it simple to prepare the NCs while also maintaining their purity. Ag NPs were prepared separately by gamma-ray irradiation and away from the chemical reducing agents. Then, PANI was prepared, \u003cem\u003ein situ\u003c/em\u003e of colloidal Ag, in bulk amount and powder form taking advantage of the simple chemical redox polymerization method.\u003c/p\u003e"},{"header":"Materials and Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eMaterials\u003c/h2\u003e \u003cp\u003eAniline monomer, ammonium persulfate (APS) 98% initiator, hydrochloric acid 35\u0026ndash;38% doping agent, and polyvinyl pyrrolidone (PVP) (MWt 100,000) capping agent were obtained from Merck, Fischer Laboratory Reagent, Fisher Scientific, BIO Basic Canada Inc, respectively. Silver nitrate (AgNO\u003csub\u003e3\u003c/sub\u003e) was obtained from Sisco Research Laboratories PVT. Ltd. India.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003eMethodology\u003c/h2\u003e \u003cdiv id=\"Sec5\" class=\"Section3\"\u003e \u003ch2\u003e\u0026bull; Synthesis of Silver colloid\u003c/h2\u003e \u003cp\u003eSilver nanoparticles colloid was synthesized following the procedure described Afify et al [\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e]. In 100 ml distilled water, 1.7 g of silver nitrate and 0.034 g of PVP were dissolved to prepare the AgNO\u003csub\u003e3\u003c/sub\u003e solution. Gamma-irradiation was applied to the solution at a dose of 50 KGy by using a Co-60 -cell-220 source. A colloidal solution of silver nanoparticles suspended in water was obtained.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec6\" class=\"Section3\"\u003e \u003ch2\u003e\u0026bull; Synthesize polyaniline/silver nanocomposites\u003c/h2\u003e \u003cp\u003eThe formed colloid was used to as a medium for the polymerization of aniline to synthesize polyaniline/silver nanocomposites (PANI/Ag NCs). The polymerization was carried out by chemical oxidative reaction in the presence of APS as an initiator and HCl as a dopping agent. The molar ratio of aniline was fixed at 1, while that of both Ag and HCl varied at 0.11 to 1 and 0.83 to 2.5, respectively, as shown in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e. Aniline was added to the Ag NPs colloid and HCl was added to the mixture with continuous stirring at room temperature for 30 min. An initiator solution was prepared by dissolving APS in distilled water. The initiator solution was drop-wise poured into the mixture to initiate the polymerization reaction with continuous stirring for 12 hours. PANI/Ag NCs were precipitated as dark green powders, which were filtrated, washed, and dried at room temperature.\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003eCharacterization techniques\u003c/h2\u003e \u003cp\u003e \u003cdiv class=\"BlockQuote\"\u003e \u003cp\u003eThe particle size distribution was determined by dynamic light scattering (DLS) in the range of 0.4\u0026ndash;10,000 nm using Malvern Zetasizer Nano, UK. UV-Vis absorption spectra were performed on Agilent Cary 60 UV-Vis Spectrophotometer. X-ray diffraction (XRD) was used to analyze the samples using Philips PW 1830 diffractometer with CuK (=\u0026thinsp;0.154 nm) radiation source operated at 35 mA and 40 kV. The particle size of Ag NPs was calculated using Debye\u0026ndash;Scherrer\u0026rsquo;s equation (D\u0026thinsp;=\u0026thinsp;0.92 λ/β cos θ), where, 0.92 is a constant, λ is the wavelength of the X-rays and β is the full width at half maximum (FWHM) of the diffraction peaks and θ the corresponding diffraction angle in radian. Fourier transform infrared (FTIR) spectra were recorded by JASCO FTIR 6100 in the range of 4000\u0026ndash;400 cm\u003csup\u003e-1\u003c/sup\u003e with 4 cm\u003csup\u003e-1\u003c/sup\u003e resolution and 50 scans with a scanning speed of 2 mm/s. TEM images were carried out by high-resolution JEOL-2100 TEM. Additionally, HR-TEM was used to analyze the silver colloid by selected area electron diffraction (SAED). Scanning micrographs were performed on Quantum Field Emission Gun 250 with Energy disperses x-rays analysis (EDX) by Ametek Holland. Shimadzu TGA-50 thermogravimetric analyzer was used to perform the thermogravimetric analysis (TGA), Columbia, EUA, under a nitrogen atmosphere at 10\u0026deg;C/min heating rate from room temperature to 600\u0026deg;C. Thin films of the NCs powder having thickness 0.5 mm were fabricated by compression molding in a hydraulic press at 170 \u003csup\u003eo\u003c/sup\u003eC and under pressure of 100 pounds/in\u003csup\u003e2\u003c/sup\u003e. The D.C. electrical conductivities of the thin films were measured by Hioki 3522-50 LCR Hi Tester (Japan). Antibacterial and antifungal activities toward (\u003cem\u003eEscherichia coli G\u003c/em\u003e\u003csup\u003e\u003cem\u003e-\u003c/em\u003e\u003c/sup\u003e and \u003cem\u003eStaphylococcus aureus G\u003c/em\u003e\u003csup\u003e\u003cem\u003e+\u003c/em\u003e\u003c/sup\u003e) and (\u003cem\u003eAsprigillus flavus\u003c/em\u003e and \u003cem\u003eCandida albicans\u003c/em\u003e) were determined using modified Kirby- Bauer disc diffusion by Hioki 3522-50 LCR Hitester (Japan). Mueller\u0026ndash;Hinton agar is used for determination of susceptibility of microorganisms to antimicrobial agents.\u003c/p\u003e \u003c/div\u003e \u003c/p\u003e \u003c/div\u003e"},{"header":"Results and discussion","content":"\u003cdiv id=\"Sec9\" class=\"Section2\"\u003e \u003ch2\u003eFormation and characterization of colloidal Ag NPs\u003c/h2\u003e \u003cp\u003eA schematic illustration of the synthesis of Ag NPs via gamma-irradiation is shown in Fig.\u0026nbsp;1. Water molecules are radiolyzed when silver nitrate solution is exposed to γ-rays. In turn, this reaction releases hydrogen atoms (H*) and hydrated electrons (e-). The latter species are capable of reducing Ag cations (Ag+) to Ag atoms (Ag\u003csup\u003eo\u003c/sup\u003e). Clusters of Ag NPs are formed as the silver nuclei grow. In order to ensure the growth and stability of the Ag NPs, PVP is used to prevent the cluster aggregation by capping on their surfaces.\u003cdiv class=\"BlockQuote\"\u003e\u003cp\u003eThe UV-Vis absorption spectrum of the synthesized Ag NPs is shown in Fig.\u0026nbsp;2a. Around 428 nm, the distinctive Ag peak is plainly visible as a broad absorption band. The combined vibration of the free electrons on Ag NPs in resonance with the incident light causes this band to arise. The lack of any other peaks in the spectrum beside the Ag peak confirms their purity. The FTIR spectrum of Ag NPs is presented in Fig.\u0026nbsp;2b. The bands at 1668 cm\u003csup\u003e-1\u003c/sup\u003e and 1041 cm\u003csup\u003e-1\u003c/sup\u003e are characteristic to the amide group C\u0026thinsp;=\u0026thinsp;O stretching and C-N stretching of PVP. The existence of a peak at around 1382 cm\u003csup\u003e-1\u003c/sup\u003e may be related to N-O stretching of the precursor AgNO\u003csub\u003e3\u003c/sub\u003e. However, the characteristic band of Ag NPs appeared at 552 cm\u003csup\u003e-1\u003c/sup\u003e. From XRD pattern (Fig.\u0026nbsp;2c) and in agreement with silver JCPDS File No. 04-0783 from ASTM, the Face Centered Cubic silver crystals of the crystallographic planes 111, 200, 220, 311, and 222 appeared at 2θ of 38.2\u0026deg;, 44.8\u0026deg;, 64.4\u0026deg;, 77.5\u0026deg;, and 81.4\u0026deg;. There were no discernible extra phases found in the XRD pattern. This displays the purity of the generated Ag NPs. The highly crystalline structure was highlighted by the sharpness of the peaks. The average particle size was determined using the main diffraction peak (111) to be 15.58 nm. The DLS graph of the prepared Ag NPs colloid is shown in Fig.\u0026nbsp;2d. The distribution sizes in the figure are extremely narrow, ranging from 7 nm to 17 nm. The scale is located in the nano size and the colloid's average particle size is 11 nm. The SEM micrograph and TEM image of the Ag NPs (Fig.\u0026nbsp;3a and Fig.\u0026nbsp;3b, respectively) showed aggregated spherical particles of 8 to 10 nm size which lies within the particle size distribution of DLS analysis. The elemental composition of Ag NPs by EDX analysis (Fig.\u0026nbsp;3c) revealed pure signals from the silver atoms. Four signal energy peaks, characteristic to Ag atoms and demonstrating the pure crystalline nature of the Ag colloid, appeared at 2.76 KeV, 3 KeV, and 3.16 and 3.35 KeV which are associated with the emission of M-shell, L\u003csub\u003eα\u003c/sub\u003e-shell, and L\u003csub\u003eβ\u003c/sub\u003e-shell electrons from silver atoms, respectively. Figure\u0026nbsp;3d displays the SAED pattern of the Ag colloid. The image shows circular rings that reflect the crystalline nature of the silver particles, which represent the (111), (200), (220), (311), (222) and (420) planes. These levels match with fcc of silver (JCPDS 04-0783).\u003c/p\u003e\u003c/div\u003e\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec10\" class=\"Section2\"\u003e \u003ch2\u003eCharacterization of PANI/Ag NCs\u003c/h2\u003e \u003cp\u003eFTIR spectra of PANI/Ag NCs are shown in Fig.\u0026nbsp;4. The characteristic bands of PANI are well observed in the spectra at 3467\u0026thinsp;\u0026minus;\u0026thinsp;3436 and 1163\u0026thinsp;\u0026minus;\u0026thinsp;1132 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e which assigned to N-H stretching, and C-N stretching, respectively. These two bands are shifted to lower wavenumbers with increasing the amount of Ag NPs in the NCs. This may be due to the interaction between the nitrogen atoms forming the stretched-bonds and Ag NPs. This interaction weakens the N-H and C-N bonds resulting their stretching at lower wavenumbers. C\u0026thinsp;=\u0026thinsp;C stretching of quinoid and benzenoid rings appeared between 1365 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e to 1583 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e. The band at 2354 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e may be related to conjugated\u0026thinsp;=\u0026thinsp;C-C\u0026thinsp;=\u0026thinsp;N stretching and the C-H aliphatic symmetric and asymmetric stretching bands are emerged at 2930 and 2863 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e, respectively. The band at 1684 cm\u003csup\u003e\u0026minus;\u0026thinsp;1\u003c/sup\u003e to 1652 may be related to PVP stabilizer used in the preparation of Ag colloid and C\u0026thinsp;=\u0026thinsp;N stretching of PANI. The shift to lower wavenumbers from NC1 to NC4 in this band proves the physical and electrostatic interactions between Ag NPs and PANI chains. The EDX analysis of PANI, NC1, NC2, NC3, and NC4 are shown in Fig.\u0026nbsp;5. The major elements appeared in the EDX spectrum of PANI are carbon, nitrogen, oxygen, and chlorine. However, three signal energy peaks appeared at 3.02 keV, 3.30 keV and 3.56 keV in NCs spectra which are associated with the emission of L-shell electrons from silver atoms. The intensity of these peaks increased with increasing the amount of Ag NPs in the NCs and the weight % rose from 16.37% in NC1 to 51.13% in NC4. Whereas, the intensity of peaks at 0.23 KeV (C K-shell), 0.36 KeV (N K-shell), 0.49 KeV (O K-shell), and 2.62 KeV (Cl K-shell) decreased and their weight % declined with increasing amount of Ag NPs in the NCs. All these results indicate the success of the aniline polymerization process on the surface of the Ag NPs in the colloid. Figure\u0026nbsp;6 demonstrates the SEM micrographs of NC1, NC2, NC3, and NC4. Images of NC1 (Fig.\u0026nbsp;6a) and NC2 (Fig.\u0026nbsp;6b) show flaky sheets of PANI with some distributed rod-like structures. Additionally, in NC1, the polymer seemed to entirely encase the Ag particles, whereas in NC2, they were just faintly visible alone. In NC3, these particles distributed throughout the polymer matrix, while in NC4 Ag NPs appeared as agglomerates. The DLS curves of PANI, NC1, NC2, NC3, and NC4 are presented in Fig.\u0026nbsp;7. PANI particles range in size from 45 nm to 71 nm, with the majority being 58 nm. Whereas, with the polymerization of aniline in the presence of the least quantity of silver, the strength and amplitude of the PANI peak declined, and a new peak with a narrower size range formed. This new peak, which varies in size from 36 nm to 50 nm with the majority at 42 nm, demonstrates the deposition of PANI layers on the Ag particles and generation of the core-shell NC1. The DLS curve of NC2 resembles that of NC1, with the PANI peak having less intensity and width and the NC peak having a stronger and wider size range. This is due to the fact that more amount of aniline polymerized on the surface of the Ag particles, which increased its amount in NC2 than NC1. As a result, less pure PANI was produced, and a shift to lower size could be seen. The absence of Ag peak implies that PANI has completely encapsulated all of the silver's particles in both NC1 and NC2. However, as the amount of silver in the polymerization medium increased, clusters of its particles started to form, which eventually broke off from the composite and sank alone. This is evidenced by the appearance of silver peaks in both NC3 and NC4. The particle size distribution profile of the NCs is in good agreement with the SEM images, which showed aggregations of silver particles in both NC3 and NC4. The XRD patterns of NC1, NC2, NC3, and NC4 are illustrated in Fig.\u0026nbsp;8. The three distinct and broad peaks, with diffraction angles 15.4\u003csup\u003eo\u003c/sup\u003e, 20.7\u003csup\u003eo\u003c/sup\u003e, and 25.5\u003csup\u003eo\u003c/sup\u003e, which correspond to crystal planes 121, 113, and 322, demonstrate the semi-crystalline nature of PANI and that these three crystal planes were the direction of most of its chains. The broadness and intensity of the peaks signify the degree of chain orientation in the plane and the population of crystallites, respectively. The detected peaks are consistent with those reported by the Joint Committee on Powder Diffraction Standards (no. 72\u0026ndash;0634). On the other hand the diffraction angles of Ag NPs were emerged at 2θ of 38.2\u0026deg;, 44.6\u0026deg;, 64.8\u0026deg;, 77.3\u0026deg;, and 81.8\u0026deg;, indicating that the aniline polymerization had no effect on their crystallinity. It is evident that when the amount of Ag in the NCs rose, the intensity of the Ag peaks increased, and vice versa for PANI.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec11\" class=\"Section2\"\u003e \u003ch2\u003eOptical properties of PANI/Ag NCs\u003c/h2\u003e \u003cp\u003eUV-Vis spectroscopy was used to examine the opto-electronic characteristics of PANI and PANI/Ag NCs and their spectra are shown in Fig.\u0026nbsp;9. The UV-Vis spectrum of PANI showed three spectral maxima at 207 nm, 373 nm, and 745 nm. The former is due to the transition of the electrons in the bonding π orbital to the antibonding π* orbital. This type of π- π* transition is associated with the conjugated systems of benzenoid structure in PANI. The second electron transition at 373 nm is caused by the non-bonding pair in an n-orbital to the antibonding π* orbital. This n\u0026ndash;π* transitions appeared in the quinonoid ring of PANI. The third broad band is ascribed to polaron/bipolaron resonance which proves that the prepared PANI is in the conductive form. However, a conjugating electron cloud is produced easily after the embedding of Ag NPs, rich in free electrons, with emeraldine salt PANI. This is induced by the presence of electrostatic interaction between PANI chains and Ag NPs which caused a large number of free electrons around Ag atoms that easily conjugate with nitrogen atoms of PANI. Therefore, a bathochromic shift in the UV-Vis spectra of the NCs is observed, where the peaks in PANI spectrum at wavelength 207 nm and 745 nm are red shifted gradually with decreasing the amount of PANI in the NC to reach 233 nm and 782 nm for NC4 associated with a hypochromic shift. The peak at 373 nm in the PANI spectrum became merged with the broad Ag peak which appeared at wavelength 432 nm. This electronic behavior of the NCs enhances their application as supercapacitors, photocatalysts, or antimicrobial agents.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec12\" class=\"Section2\"\u003e \u003ch2\u003eThermal properties of PANI/Ag NCs\u003c/h2\u003e \u003cp\u003eTGA profiles of PANI and the prepared NCs are depicted in Fig.\u0026nbsp;10. All samples show a significant weight loss at temperatures below 100\u0026deg;C, which is caused by the evaporation of the absorbed water and some volatiles. This weight loss amounted to 15% for pure PANI and decrease with increasing the amount of Ag in the NCs. When the temperature reached 170\u0026deg;C, the dopant began to decompose until 250\u0026deg;C, and PANI chains were completely deprotonated. At about 370\u0026deg;C, the main backbone chains of PANI degraded. It is visually evident from the TGA curves that Ag NPs greatly enhanced the thermal stability of PANI where the mass loss at the deprotonation of PANI decreased from 25% (PANI) to only 12% (NC4). Also, the mass loss at the degradation of PANI reduced from 60% (PANI) to 34% (NC4). The residue at 700 \u003csup\u003eo\u003c/sup\u003eC was only 12% for PANI, whereas it reached more than 50% in NC4.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec13\" class=\"Section2\"\u003e \u003ch2\u003eElectrical properties of PANI/Ag NCs\u003c/h2\u003e \u003cp\u003eThe DC conductivity results of Ag NCs are listed in Table\u0026nbsp;\u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e and illustrated in Fig.\u0026nbsp;11. The influence of two different factors on the electrical conductivity has been studied, namely the effect of both dopant concentration (Fig.\u0026nbsp;11a) and the silver concentration (Fig.\u0026nbsp;11b) on the nanocomposites, which reveals:\u003c/p\u003e \u003cp\u003e \u003cul\u003e \u003cli\u003e \u003cp\u003eWith the increase of the molar ratio of HCl in the NCs from 0.83 to 2.5, the electrical conductivity increases steadily (Fig.\u0026nbsp;11a), which shows the obvious role of dopant in increasing the conductivity.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eThe electrical conductivity results of the NCs with doping molar ratio of 2.5 showed that they can be used as excellent semiconductors.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eAlso, good conductivity was obtained in the NCs with a dopant molarity of 0.83 when ratios of 0.11 and 0.23 mol Ag NPs were used in the NCs. This qualifies both NC1 and NC2 to be used as semiconductors.\u003c/p\u003e \u003c/li\u003e \u003cli\u003e \u003cp\u003eAlthough it was anticipated that the D.C. conductivity would increase as the molar ratio of silver in the NCs increased, it was discovered that this was not the case for either of the two doping acid ratios (Fig.\u0026nbsp;11b). This can be explained by the extraordinary surface area and energy of minute size Ag NPs led to strengthen the interaction between their particles and aggregations occurred as illustrated in SEM images (Fig.\u0026nbsp;6), while at the same time the interaction towards the PANI matrix had been weakened. Therefore, as the content of Ag NPs increased, their accumulation/agglomeration in the polymer NCs increased, and thus the electrical conductivity decreased [\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e]. Also, as the Ag NPs content increased, the PANI decreased such that it was not sufficient to coat efficiently Ag NPs, thus Ag NPs became susceptible to agglomeration. Accordingly, increasing the PANI content may be helpful.\u003c/p\u003e \u003c/li\u003e \u003c/ul\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\u003eChemical composition and electrical properties of PANI/Ag nanocomposites\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=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eNanocomposite\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"3\" nameend=\"c4\" namest=\"c2\"\u003e \u003cp\u003eMolar ratio of PANI/Ag NCs\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eDC (S/cm)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eAg\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eAniline\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eDopant\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNC1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.83\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.8 x 10\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNC2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.23\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.83\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.4 x 10\u003csup\u003e\u0026minus;\u0026thinsp;3\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNC3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.58\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.83\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e4.1 x 10\u003csup\u003e\u0026minus;\u0026thinsp;5\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNC4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e0.83\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e8.5 x 10\u003csup\u003e\u0026minus;\u0026thinsp;7\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNC5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e2.50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e5.6 x 10\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNC6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.23\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e2.50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e3.6 x 10\u003csup\u003e\u0026minus;\u0026thinsp;2\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNC7\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.58\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e2.50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e6.8 x 10\u003csup\u003e\u0026minus;\u0026thinsp;3\u003c/sup\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNC8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e1.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c4\"\u003e \u003cp\u003e2.50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e1.5 x 10\u003csup\u003e\u0026minus;\u0026thinsp;3\u003c/sup\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 \u003c/div\u003e \u003cdiv id=\"Sec14\" class=\"Section2\"\u003e \u003ch2\u003eAntimicrobial properties of PANI/Ag NCs\u003c/h2\u003e \u003cp\u003eTable\u0026nbsp;\u003cspan refid=\"Tab2\" class=\"InternalRef\"\u003e2\u003c/span\u003e and Fig.\u0026nbsp;12 show the antibacterial and antifungal activities of the synthesized PANI/Ag NCs. All NCs showed antibacterial effect, while some of them which contained high doses of Ag NPs showed some antifungal effect. All the prepared composites displayed high levels of bacterial resistance, which peaked when NC4 was used, as it had an effectiveness of 124% against \u003cem\u003eStaphylococcus aureus\u003c/em\u003e and 84% against \u003cem\u003eEscherichia coli\u003c/em\u003e. It is also clear from the results that the efficiency of the composites against bacteria increased with the increase silver content. However, the NCs showed much less resistance to fungi, such that many of them did not show any resistance, nevertheless by increasing the percentage of silver in the NCs, its efficiency increased. This indicates that the strongest factor for resisting bacteria or fungi in these composites lies in silver content. The effectiveness of silver as an antibacterial lies in its deadly effect by making holes in the cell wall of the bacterial cell, causing its destruction upon entering it. Silver ions bind to basic components of the cell such as DNA, and prevent bacteria from performing even their most basic functions.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab2\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eAntibacterial and antifungal activities of PANI/Ag NCs .\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"10\"\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c1\" colnum=\"1\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c2\" colnum=\"2\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c3\" colnum=\"3\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c4\" colnum=\"4\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c5\" colnum=\"5\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c6\" colnum=\"6\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c7\" colnum=\"7\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c8\" colnum=\"8\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c9\" colnum=\"9\"\u003e\u003c/div\u003e \u003cdiv align=\"left\" class=\"colspec\" colname=\"c10\" colnum=\"10\"\u003e\u003c/div\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colspan=\"2\" morerows=\"1\" nameend=\"c2\" namest=\"c1\" rowspan=\"2\"\u003e \u003cp\u003eSample\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"8\" nameend=\"c10\" namest=\"c3\"\u003e \u003cp\u003eInhibition zone diameter ( mm / mg sample )\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e \u003cp\u003e\u003cem\u003eEscherichia coli (G\u003c/em\u003e\u003csup\u003e\u003cem\u003e\u0026minus;\u003c/em\u003e\u003c/sup\u003e\u003cem\u003e)\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c6\" namest=\"c5\"\u003e \u003cp\u003e\u003cem\u003eStaphylococcus aureus (G\u003c/em\u003e\u003csup\u003e\u003cem\u003e+\u003c/em\u003e\u003c/sup\u003e\u003cem\u003e)\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c8\" namest=\"c7\"\u003e \u003cp\u003e\u003cem\u003eAspergillus flavus\u003c/em\u003e\u003c/p\u003e \u003cp\u003e\u003cem\u003e(Fungus)\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"2\" nameend=\"c10\" namest=\"c9\"\u003e \u003cp\u003e\u003cem\u003eCandida Albicans (Fungus)\u003c/em\u003e\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003e\u003cb\u003eControl : DMSO\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e \u003cp\u003e0.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c6\" namest=\"c5\"\u003e \u003cp\u003e0.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c8\" namest=\"c7\"\u003e \u003cp\u003e0.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c10\" namest=\"c9\"\u003e \u003cp\u003e0.0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e\u003cb\u003eStandard\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003eAmpicillin antibacterial agent\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e \u003cp\u003e25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c6\" namest=\"c5\"\u003e \u003cp\u003e21\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c8\" namest=\"c7\"\u003e \u003cp\u003e--\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c10\" namest=\"c9\"\u003e \u003cp\u003e--\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003e\u003cb\u003eAmphotericin B Antifungal agent\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c4\" namest=\"c3\"\u003e \u003cp\u003e--\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c6\" namest=\"c5\"\u003e \u003cp\u003e--\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c8\" namest=\"c7\"\u003e \u003cp\u003e16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c10\" namest=\"c9\"\u003e \u003cp\u003e19\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003e\u003cb\u003eSample\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u003cb\u003e% to Standard\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e\u003cb\u003e% to Standard\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e0.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e\u003cb\u003e% to Standard\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003e0.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e\u003cb\u003e% to Standard\u003c/b\u003e\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eNC1\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e44\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e57\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e0.0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eNC2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e60\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e71.4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e52.6\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eNC3\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e22\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e88\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e20\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e95\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e62.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e52.6\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eNC4\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e21\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e84\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e26\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e123.8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e62.5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e57.9\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eNC5\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e48\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e47.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e0.0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eNC6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e39\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e10\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e49.6\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e0.0\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colspan=\"2\" nameend=\"c2\" namest=\"c1\"\u003e \u003cp\u003eNC8\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003e15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e60\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e \u003cp\u003e76.2\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e \u003cp\u003e0.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e \u003cp\u003e0.0\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e9\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e \u003cp\u003e47.4\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\u003e \u003cul\u003e \u003cli\u003e \u003cp\u003e \u003cem\u003eValues with respect to standards, below 30% is considered weak, from 30\u0026ndash;60% and over 60% are considered medium and high, respectively.\u003c/em\u003e \u003c/p\u003e \u003c/li\u003e \u003c/ul\u003e \u003c/p\u003e \u003c/div\u003e"},{"header":"Conclusion","content":"\u003cp\u003ePolyaniline / Ag nanocomposites were fabricated in sequential steps. The silver colloid was firstly prepared by gamma-irradiation of the precursor and by using PVP as a capping agent, and then aniline monomers were chemically polymerized in the silver colloid. Different molar ratios of aniline to Ag and HCl dopant to aniline were used. FTIR, UV-Visible, EDX, and XRD analysis confirmed the formation of silver nanoparticles in the colloid. The size of the spherical-shaped silver particles was ranged from 7 nm to 17 nm as illustrated from DLS, TEM, and XRD analysis. The aim of the research work was to modify the thermal, optical, electrical and antimicrobial properties of the materials used in the nanocomposites. The silver particles significantly enhanced the thermal stability of polyaniline at all stages of thermal degradation of polyaniline (as evidenced from TGA profiles). The presence of electrostatic interaction between polyaniline chains and silver nanoparticles was confirmed from the UV-Visible spectroscopy where a conjugating electron cloud was produced after the impregnation of silver nanoparticles, rich in free electrons, with emeraldine salt polyaniline. This induced a large number of free electrons around silver atoms to conjugate with the nitrogen atoms of polyaniline. The electrical conductivity increased with increasing of the dopant. Due to the minute particle size of the Ag colloid, some agglomeration of Ag NPs occurred in the nanocomposites, which increased with increasing of Ag concentration in the nanocomposites and resulting in a decrease in the electrical conductivity. The prepared nanocomposites have excellent antibacterial activity to \u003cem\u003eE-Coli (Gram -) and S. aureus (Gram +)\u003c/em\u003e but medium activity to \u003cem\u003eCandida albicans fungus.\u003c/em\u003e The fabricated nanocomposites can be used in food packaging applications, supercapacitors, photocatalysts, antimicrobial agents and sensors.\u003c/p\u003e \u003cdiv id=\"Sec16\" class=\"Section2\"\u003e \u003ch2\u003eData availability\u003c/h2\u003e \u003cp\u003eThe data are available from the corresponding author on reasonable request. [Name: Samir M.M. Morsi, e-mail: [email protected]].\u003c/p\u003e \u003c/div\u003e"},{"header":"Declarations","content":"\u003cp\u003e \u003ch2\u003eCompeting interests\u003c/h2\u003e \u003cp\u003eThe authors declare no competing interests.\u003c/p\u003e \u003c/p\u003e\u003ch2\u003eAuthor Contribution\u003c/h2\u003e\u003cp\u003eSamir M. M. Morsi: Data Curation, Writing \u0026ndash; original draft, Writing \u0026ndash; review and editing, Visualization.Rajia Mohsen: Visualization, Conceptualization, Resources, Supervision, Methodology, Data Curation, Writing \u0026ndash; original draft, review and editing.Hazem El-Sherif: Survey.Noha Deghiedy: Synthesis of silver nanoparticals.Ahmed Ghoneim: Carried out the electrical measurements.\u003c/p\u003e\u003ch2\u003eAcknowledgement\u003c/h2\u003e \u003cp\u003eThe authors express their great appreciation to the National Research Center for the financial support of this research article derived from project No.10050408.\u003c/p\u003e\u003ch2\u003eData Availability\u003c/h2\u003e\u003cp\u003eThe data are available from the corresponding author on reasonable request. [Name: Samir M.M. Morsi, e-mail: [email protected]].\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eManirul Haque SK, Ardila-Rey JA, Umar Y, Mas\u0026rsquo;ud AA, Muhammad-Sukki F, Jume BH, Rahman H, Bani NA. Application and suitability of polymeric materials as insulators in electrical equipment. Energies. 2021; 14: 2758.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLiu Z, Poyraz S, Zhang L, Zhang X. Conducting polymer-metal nanocomposites synthesis and their sensory applications, Current Organic Chemistry, 2013; 17: 2256\u0026ndash;2267.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMelimite V, Buruiana T, Morau LD, Buruiana EC. Silver-polymer composite materials with antimicrobial properties. Design Journal of nanomaterials and biostructures. 2011; 6: 213\u0026ndash;223.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eMorsi SMM, Emira HS, El-Sawy SM, Mohsen RM, Khorshed LA. 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Chinese Journal of Chemical Physics. 2010; 23: 701\u0026ndash;706.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eAshraf MA, Peng W, Zare Y, Rhee KY. Effects of size and aggregation/agglomeration of nanoparticles on the interfacial/interphase properties and tensile strength of polymer nanocomposites, Nanoscale Research Letters. 2018; 13: 214.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"nanocomposite, conductive polymer, silver colloid, polyaniline, antimicrobial properties","lastPublishedDoi":"10.21203/rs.3.rs-4007882/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-4007882/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eA simple and new way was used to modify the thermal, electrical, optical, and antimicrobial properties of conductive polyaniline by embedding a nanosized metallic material in the polymeric matrix. The sequence of fabrication was as follows: first, preparing a silver colloid by gamma-irradiating the precursor and then, aniline monomer was polymerized in the colloid using different molarities of the dopant and the silver itself. The mentioned properties of Ag colloid and the conductive polymer / Ag nanocomposites (NCs) were studied using TGA, electrical measurements, UV-Vis spectroscopy, FTIR, TEM, SEM, DLS, SAED, and EDX. The particle size distribution of the Ag colloid is ranged from 7 to 17 nm. The results showed an increase in the D.C conductivity of NCs thin films with increasing of dopant. All the prepared NCs exhibited medium to high antibacterial activity against \u003cem\u003eEscherichia coli\u003c/em\u003e and \u003cem\u003eStaphylococcus aureus\u003c/em\u003e reaching the maximum efficiency at PANI: Ag: dopant molar ratio of 1:1:0.83. Also, an electrostatic interaction has been generated between the conductive PANI chains and the free electrons around Ag NPs leading to a conjugating electron cloud in the produced NCs. This electronic behavior facilitates the use of the prepared NCs as supercapacitors, sensors, photocatalysts, or antibacterial materials.\u003c/p\u003e","manuscriptTitle":"Thermal, electrical, optical, and antimicrobial studies of PANI/Ag nanocomposites synthesized by polymerization of aniline on γ-irradiated and PVP-capped Ag colloid","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2024-04-15 11:33:02","doi":"10.21203/rs.3.rs-4007882/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"e30c61a2-d4f3-4d72-a516-1f8bef7c47a3","owner":[],"postedDate":"April 15th, 2024","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":30614699,"name":"Physical sciences/Chemistry"},{"id":30614700,"name":"Physical sciences/Materials science"}],"tags":[],"updatedAt":"2024-05-08T06:23:17+00:00","versionOfRecord":[],"versionCreatedAt":"2024-04-15 11:33:02","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-4007882","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-4007882","identity":"rs-4007882","version":["v1"]},"buildId":"qtupq5eGEP_6zYnWcrvyt","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}