Silver/poly(N‐vinyl‐2‐pyrrolidone) hydrogel nanocomposites obtained by electrochemical synthesis of silver nanoparticles inside the polymer hydrogel aimed for biomedical applications

Silver nanoparticles were produced inside a poly(N‐vinyl‐2‐pyrrolidone) hydrogel (PVP) by an innovative method based on the electrochemical reduction of Ag⁺ ions within the swollen PVP hydrogel. UV‐visible spectroscopy showed the highest value of the absorbance intensity and the lowest values of the wavelength of the absorbance maximum and the full width at the half‐maximum absorbance for the Ag/PVP nanocomposite obtained at 200 V during 4 min. Cyclic voltammetry results suggested an adequate entrapment of the silver nanoparticles. The mechanical properties under bioreactor conditions of the Ag/PVP nanocomposite suggested the possibility of wound dressing application. Silver release from Ag/PVP nanocomposites was confirmed under static conditions as well as by their antimicrobial activity against Staphylococcus aureus. POLYM. COMPOS., 35:217–226, 2014. © 2013 Society of Plastics Engineers     

Poly(9‐vinylcarbazole)/silver composite nanotubes and networks formed at the air–water interface

Silver‐nanoparticle‐doped poly(9‐vinylcarbazole) (PVK) nanocomposites were prepared via the reduction of Ag⁺ ions and the self‐assembly of PVK on AgNO₃ aqueous solution surfaces. The formed composite nanostructures depended strongly on the experimental temperature. Thick round disks of PVK surrounded by discrete Ag nanoparticles and/or with irregular holes formed at room temperature; nanotubes and micronetworks doped with Ag nanoparticles formed at about 30–40°C, and networks formed at higher temperature. Further investigation revealed that the nanotubes were transformed from thin round disks. The length of the PVK/Ag composite nanotubes were longer than 10 μm, and the average size of the embedded Ag nanoparticles was found to be about 3.5 nm. The composite networks were composed of round pores with diameters of several hundred nanometers and fine silver nanoparticles embedded in the thin polymer films that covered the pores. The formation of the nanotubes was a very interesting self‐assembly phenomenon of the polymer at the air–water interface that has not been reported before. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

A Novel Approach to Prepare Poly(Vinyl Acetate)/Ag Nanocomposite for Effective Antimicrobial Coating Applications

Polyvinyl acetate nanocomposites were successfully prepared based on silver nanoparticles. First, silver nanoparticles were directly prepared during the in situ emulsion polymerization of vinyl acetate monomer using AgNO₃ as a source of Ag⁺ ions and poly(vinyl alcohol) was used for dual functions as emulsifier for emulsion polymerization and as a stabilizing agent, trisodium citrate (C₆H₅O₇Na₃) was used as reducing agent for Ag⁺ ions during the polymerization process. The prepared polyvinyl acetate/Ag nanocomposites were assessed using X-ray diffraction, scanning electron microscopy, Fourier transform infrared, transmission electron microscopy, and ultraviolet spectra. The antibacterial properties of the prepared polyvinyl acetate/Ag nanocomposites were investigated as antimicrobial activity against pathogenic bacteria, i.e., Staphylococcus aureus (G^+ve bacteria) and Escherichia coli (G^?ve bacteria). These polyvinyl acetate nanocomposites could be used as a promising material for enhanced and continuous antibacterial applications as coating and packaging materials.     

Preparation and antibacterial activity of polyvinyl alcohol/regenerated silk fibroin composite fibers containing Ag nanoparticles

Polyvinyl alcohol (PVA)/regenerated silk fibroin (SF)/AgNO₃ composite nanofibers were prepared by electrospinning. A large number of nanoparticles containing silver were generated in situ and well‐dispersed nanoparticles were confirmed by transmission electron microscopy (TEM) intuitionally. Ultraviolet (UV)‐visible spectroscopy and X‐ray diffraction (XRD) patterns indicated that nanoparticles containing Ag were present both in blend solution and in composite nanofibers after heat treatment and after subsequent UV irradiation. By annealing the nanofibers, Ag⁺ therein was reduced so as to produce nanoparticles containing silver. By combining heat treatment with UV irradiation, Ag⁺ was transformed into Ag clusters and further oxidized into Ag₃O₄ and Ag₂O₂. Especially size of the nanoparticles increased with heat treatment and subsequent UV irradiation. This indicated that the nanoparticles containing silver could be regulated by heat treatment and UV irradiation. The antimicrobial activity of heat‐treated composite nanofibers was evaluated by Halo test method and the resultant nanofibers showed very strong antimicrobial activity. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Highly Efficient Room Temperature Synthesis of Silver‐Doped Zinc Oxide (ZnO:Ag) Nanoparticles: Structural,Optical, and Photocatalytic Properties

Synthesis of silver‐doped zinc oxide (ZnO:Ag) nanoparticles through precipitation method has been reported. The synthesis was conducted at room temperature and no subsequent thermal treatment was applied. ZnO nanoparticles were characterized by X‐ray diffraction (XRD), transmission electron microscopy (TEM), X‐ray photoelectron spectroscopy (XPS), fourier transmission infrared spectroscopy (FTIR), and ultraviolet‐visible (UV–Vis) spectroscopy. Detailed crystallographic investigation was accomplished through Rietveld refinement. The effect of silver content on structural and optical properties of resultant ZnO nanoparticles has been reported. It was found that silver doping results in positional shifts for the XRD peaks and the absorption band edge of ZnO. These were attributed to the substitutional incorporation of Ag⁺ ions into Zn²⁺ sites within the ZnO crystal. In addition, higher silver incorporation resulted in smaller size for ZnO nanoparticles. The photocatalytic activity of the ZnO:Ag nanoparticles was also determined by methylene orange (MO) degradation studies and compared to that of undoped ZnO. Improved photocatalytic activity was obtained for ZnO:Ag nanoparticles. It has been shown that an optimum amount of silver dopant is required to obtain maximum photocatalytic activity.     

Integrated PLGA–Ag nanocomposite systems to control the degradation rate and antibacterial properties

Biodegradable polymer based nanocomposite materials have attracted much attention since they can be used for biomedical and pharmaceutical applications. In order to have highly integrated PLGA nanocomposite materials, silver colloidal nanoparticles were prepared in chloroform starting from silver nitrate and using polyvinylpyrrolidone as reduction and capping agent. TEM and AFM imaging give information on the size distribution of the silver nucleus (7.0 nm) and the capping shell (8.2–10.7 nm). PLGA–Ag nanocomposites were prepared upon addition of 1 or 3% wt of silver nanoparticles to the PLGA/chloroform suspension. The effect of silver loading on polymer degradation was studied following the mass loss and the morphology of nanocomposite films at different degradation stages. The concentrations of Ag⁺, which is released during nanocomposite degradation, were monitored and analyzed through the diffusion model, to have insight on the degradation kinetics. The release rate, and likely the degradation rate, was reduced at higher silver loading. Bacterial growth tests indicated that the cell growth is inhibited in the presence of PLGA–Ag nanocomposites and the efficiency is correlated to Ag⁺ release. Thus, controlling the nanoparticle loading, a tunable degradation and antibacterial action can be designed. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 1185‐1193, 2013     

In situ fabrication of polyaniline‐silver nanocomposites using soft template of sodium alginate

Polyaniline (PANI)‐Ag nanocomposites were synthesized by in situ chemical polymerization approach using ammonium persulfate and silver nitrate as oxidant. Characterizations of nanocomposites were done by ultraviolet–visible ( UV–vis), Fourier transform infrared (FTIR), X‐ray diffraction (XRD), scanning electron microscopy, and transmission electron microscopy (TEM). UV–vis, XRD and FTIR analysis established the formation of PANI/Ag nanocomposites and face‐centered‐cubic phase of silver. PANInanofibers were of average diameter ～ 30 nm and several micrometers in length. Morphological analysis showed that the spherical‐shaped silver nanoparticles decorate the surface of PANI nanofibers. Silver nanoparticles of average diameter ～ 5–10 nm were observed on the TEM images for the PANI‐Ag nanocomposites. Such type of PANI‐Ag nanocomposites can be used as bistable switches as well as memory devices. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

A novel method for preparing silver/poly(siloxane‐b‐methyl methacrylate) nanocomposites with multiple properties in the DMF‐toluene mixture solvent

A novel method for preparing silver/poly(siloxane‐b‐methyl methacrylate) (Ag/(PDMS‐b‐PMMA)) hybrid nanocomposites was proposed by using the siloxane‐containing block copolymers as stabilizer. The reduction of silver nitrate (AgNO₃) was performed in the mixture solvent of dimethyl formamide (DMF) and toluene, which was used to dissolve double‐hydrophobic copolymer, as well as served as the powerful reductant. The presence of the PMMA block in the copolymer indeed exerted as capping ligands for nanoparticles. The resultant nanocomposites exhibited super hydrophobicity with water contact angle of 123.3^° and the thermogravimetry analysis (TGA) revealed that the resultant nanocomposites with more PDMS were more heat‐resisting. Besides, the antimicrobial efficiency of the most desirable nanocomposite (Ag/PDMS₆₅‐b‐PMMA₃₀ loaded with 7.3% silver nanoparticle) could reach up to 99.4% when contacting with escherichia coli within 120 min. As a whole, the resultant nanocomposites by the integration of excellent properties of silver nanoparticles as well as siloxane‐block copolymers can be a promising for the development of materials with hydrophobic, heat‐resisting and outstanding antibacterial properties from the chemical product engineering viewpoint. © 2013 American Institute of Chemical Engineers AIChE J, 59: 4780–4793, 2013     

Gelatin‐g‐poly(methyl methacrylate)/silver nanoparticle hybrid films and the evaluation of their antibacterial activity

We designed and prepared novel hybrid films of nanoparticles consisting of gelatin‐g‐poly(methyl methacrylate) (PMMA)/silver (Ag) polymers with ordered nanoporous, higher antibacterial activities. First, the gelatin‐grafted PMMA microspheres were fabricated with the in situ copolymerization of gelatin and alkenes under radical initiation, which acted as a stabilizer and regulator for Ag nanoparticle growth. Then, silver nitrate was entrapped in a copolymerization system at 40°C for 30 min. Finally, the gelatin‐g‐PMMA/Ag polymer hybrid films were prepared by the reduction of Ag⁺ with hydrazine, followed by emulsion solidification. The antibacterial activities of the gelatin‐g‐PMMA/Ag polymer hybrid films against Escherichia coli and Staphylococcus aureus were found with the disc diffusion method and colony count assays to be clear and lasting. In this study, our work not only presented a good example of a nanoporous antibacterial film material but also provided a facile method for making use of gelatin and metal/inorganic self‐assemble properties in graft copolymerization to prepare functional polymer hybrids, such as antibacterial, antithrombogenic, and dot‐quantum effect materials. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

In vitro silver ion release kinetics from nanosilver/poly(vinyl alcohol) hydrogels synthesized by gamma irradiation

A nanosilver (nano‐Ag)/poly(vinyl alcohol) (PVA) hydrogel device was synthesized with γ irradiation because it is a highly suitable tool for enhanced nano‐Ag technologies and biocompatible controlled release formulations. The amount of the Ag⁺ ions released in vitro by the nano‐Ag/PVA hydrogel device was in the antimicrobial parts per million concentration range. The modeling of the Ag⁺ ion release kinetics with the elements of the drug‐delivery paradigm revealed the best fit solution (R² > 0.99) for the Kopcha and Makoid–Banakar's pharmacokinetic dissolution models. The term A/B, derived from the Kopcha model, indicated that the nano‐Ag/PVA hydrogel was mainly an Ag⁺‐ion diffusion‐controlled device. Makoid–Banakar's parameter and the short time approximated Ag⁺‐ion diffusion constant reflected the importance of the size of the Ag nanoparticles. However, it appeared that the cell oxidation potential of the Ag nanoparticles depended on the diffusion characteristics of the fluid penetrating into the Ag/PVA nanosystem. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40321.     

Tuned interactions of silver nanoparticles with ZSM-5 zeolite by adhesion-promoting poly(acrylic acid) deposited by electrospray ionization (ESI)

The electrospray ionization (ESI) method was used for deposition of thin films of poly(acrylic acid) (PAA) on Cu/ZSM-5 (5 wt.% Cu) and Ag–Cu/ZSM-5 (1 wt.% Ag and 4 wt.% Cu) composites. For comparative purposes, the ZSM-5 zeolite was synthesized under hydrothermal conditions and loaded with PAA under the same treating conditions as the composites. This method allowed the formation of uniform polymer films of controlled thickness on conductive substrates. The structural characteristics were characterized by X-ray photoelectron spectroscopy, Fourier-transform infrared spectroscopy, atomic force microscopy and X-ray diffraction (XRD). The deposited PAA layer over ZSM-5 acts as a common dispersing and stabilizing agent through coordination-driven guest-templated polymer via interaction of Ag⁺ and Cu²⁺ with carboxylic acid groups, thus increasing and controlling the adhesion and the release of metallic species. A short exposure to light and temperature has reduced the metal ions to Cu⁰ and Ag⁰ metallic nanoparticles. The results of XRD analysis let suggest that the interaction of Cu and Ag with carboxylic groups of PAA inhibits the formation of large metallic silver particles. These samples were being studied for their potential as antibacterial agents toward the bacterial strains such as Staphylococcus pneumonia, Bacillus subtilis, Escherichia coli and Pseudomonas aeruginosa as Gram positive and Gram negative bacteria, respectively. Aspergillus fumigatus and Candida albicans as Fungi were also evaluated. The Cu/ZSM-5 and Ag–Cu/ZSM-5 nanocomposites coated with a 10 nm thick PAA layer exhibit significant antibacterial activity.     

Poly(2‐acrylamido glycolic acid‐co‐2‐acrylamido‐2‐methyl‐1‐propane sulfonic acid): Synthesis,characterization, and retention properties for environmentally impacting metal ions

Poly(2‐acrylamido glycolic acid‐co‐2‐acrylamido‐2‐methyl‐1‐propane sulfonic acid) [P(AGA‐co‐APSA)] was synthesized by radical polymerization in an aqueous solution. The water‐soluble polymer, containing secondary amide, hydroxyl, carboxylic, and sulfonic acid groups, was investigated, in view of their metal‐ion‐binding properties, as a polychelatogen with the liquid‐phase polymer‐based retention technique under different experimental conditions. The investigated metal ions were Ag⁺, Co²⁺, Ni²⁺, Cu²⁺, Zn²⁺, Cd²⁺, Pb²⁺, and Cr³⁺, and these were studied at pHs 3, 5, and 7. P(AGA‐co‐APSA) showed efficient retention of all metal ions at the pHs studied, with a minimum of 60% for Co(II) at pH 3 and a maximum close to 100% at pH 7 for all metal ions. The maximum retention capacity (n metal ion/n polymer) ranged from 0.22 for Cd²⁺ to 0.34 for Ag⁺. The antibacterial activity of Ag⁺, Cu²⁺, Zn²⁺, and Cd²⁺ polymer–metal complexes was studied, and P(AGA‐co‐APSA)–Cd²⁺ presented selective antibacterial activity for Staphylococcus aureus with a minimum inhibitory concentration of 2 μg/mL. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Antimicrobial properties of silver nanoparticles synthesized by bioaffinity adsorption coupled with TiO2 photocatalysis

BACKGROUND: On the basis of effective bioaffinity adsorption of Ag⁺, silver nanoparticles (Ag NPs) were synthesized on the surface of chitosan‐TiO₂ adsorbent (CTA) by TiO₂ photocatalysis for crystal growth. RESULTS: Among the microstructure characterizations of the resulting silver nanoparticles‐ loaded chitosan‐TiO₂ adsorbent (Ag‐CTA), X‐ray diffraction (XRD) and scanning electron microscopy (SEM) equipped with energy dispersive X‐ray (EDX) revealed the formation of metallic Ag on the CTA, which was further confirmed by the surface plasmon resonance of Ag NPs in the UV‐visible absorption spectrum. The underlying mechanism behind the formation of Ag NPs on the CTA by TiO₂ photoreduction was studied by Fourier transform infrared (FTIR) spectroscopy. The distinctive feature of Ag‐CTA after adsorption was the highly efficient antimicrobial activity in inactivating different test strains. In the case of Escherichia coli, 1.50 mg 1.67 wt% Ag‐CTA could totally inhibit 1.0–1.2 × 10⁷ colony forming units (CFU) in 100 mL nutrient medium, which was superior to that previously reported. CONCLUSIONS: CTA effectively adsorbed the precious metal ion Ag⁺ onto active imprinting sites on the adsorbent and then exerted efficient antimicrobial effects against diverse microbes. This research will be useful for designing a novel CTA‐based wastewater treatment for multi‐functional performance. Copyright © 2010 Society of Chemical Industry     

Polyelectrolytes with sulfonate groups obtained by chemical modification of chitosan useful in green synthesis of Au and Ag nanoparticles

Usually the metal nanoparticles are obtained by different chemical reactions that are not environmentally friendly. This paper describes the synthesis of two polyelectrolytes with sulfonate groups in ortho‐position and in ortho‐ and para‐positions, which were obtained by chemical modification of chitosan. They were used in the green synthesis of Au and Ag nanoparticles by colloidal method in aqueous solution. Polyelectrolytes were used as reducing agents of Au³⁺ and Ag⁺ ions and as stabilizing agents of Ag and Au nanoparticles. The hydroxyl and imine groups in the polyelectrolytes are reducing agents of Au³⁺ and Ag⁺ ions while the sulfonate groups and the polymer backbone stabilized Au and Ag nanoparticles. Polyelectrolyte 1, which has sulfonate group in ortho‐position, favors the obtaining of anisotropic Au nanoparticles with an average size of 19 nm. While the polyelectrolyte 2, with two sulfonate groups in the ortho‐ and para‐positions, yielded quasi‐spherical Au nanoparticles with an average size of 14 nm. In general, Ag nanoparticles stabilized with both polyelectrolytes, show quasi‐spherical forms with good control in size. Finally, both polyelectrolytes have the ability to protect the Au and Ag nanoparticles allowing obtaining colloidal solutions that are stable for several months. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45240.     

Synthesis of ion‐imprinting chitosan/PVA crosslinked membrane for selective removal of Ag(I)

A novel ion‐imprinted membranes were synthesized for selective removal and preconentration for Ag(I) ions from aqueous solutions. The membranes were obtained via crosslinking of chitosan (CS), PVA, and blend chitosan/PVA using glutaraldehyde (GA) as crosslinker. The FTIR spectra were used to confirm the membrane formation. Comparing with the nonimprinted membranes, Ag(I)‐imprinted CS and CS/PVA has higher removal capacity and selectivity for Ag⁺ ions. An enhancement in the Ag⁺ removal capacity by ～ 20% (from 77.8 to 94.4 mg g^–1) and ～ 50% (from 83.9 to 125 mg g^–1) was found in the Ag(I)‐imprinted CS and Ag(I)‐imprinted CS/PVA membranes, respectively, when compared with the nonimprinted membranes. Removal equilibra was achieved in about 40 min for the non‐ and ion‐imprinted CS/PVA. The pH and temperature significantly affected the removal capacity of ion‐imprinted membrane. The relative selectivity coefficient values of Ag⁺/Cu²⁺ and Ag⁺/Ni²⁺ are 9 and 10.7 for ion‐imprinted CS membrane and 11.1 and 15 for ion‐imprinted CS/PVA membrane when compared with nonimprinted membranes. The imprinted membranes can be easily regenerated by 0.01M EDTA and therefore can be reused at least five times with only 15% loss of removal capacity. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Preparation and Characterization of Silver‐Doped Cu(In,Ga)Se2 Films via Nonvacuum Solution Process

Cu(In,Ga)Se₂ films doped with different contents of silver ions (Ag⁺) were successfully prepared using nonvacuum spin coating followed by selenization at elevated temperatures. Increasing the Ag⁺ ion content increased the lattice parameters of the chalcopyrite structure, and shifted the A1 mode in the Raman signals to low frequencies. The band gaps of the prepared (Ag,Cu)(In,Ga)Se₂ (ACIGS) films were considerably increased, thereby increasing the open‐circuit voltage (V_oc) of the solar cells. As Ag⁺ ion content increased, the microstructures of ACIGS films became densified because the formed (Cu,Ag)₂In alloy phase with a low melting point facilitated liquid‐phase sintering. The evaporation of selenium species was correspondingly suppressed in the films during selenization, thereby reducing the selenium vacancies. The improvement in the microstructures and the defects of ACIGS films increased short‐circuit current (J_sc) and fill factor of the solar cells. The spectral response of the solar cells was also enhanced remarkably. This study demonstrated that incorporation of Ag⁺ ions into Cu(In,Ga)Se₂ films substantially improved the efficiency of the solar cells.     

Influence of the Eu2+ on the Silver Aggregates Formation in Ag+–Na+ Ion‐Exchanged Eu3+‐Doped Sodium–Aluminosilicate Glasses

Europium‐doping sodium–aluminosilicate glasses are prepared by melt‐quenching method, in which europium ions were spontaneously reduced from their trivalent to divalent state. The silver was introduced into glasses by Ag⁺–Na⁺ ion exchange and the interactions between europium ions and silver species were investigated. Owing to energy transfer (ET) from Ag⁺/silver aggregates to Eu³⁺, significant enhancements of Eu³⁺ emission were observed for 285/350‐nm excitation, respectively. The divalent europium ions promote the formation of silver aggregates in the process of ion exchange.     

Novel microfibrous‐structured silver catalyst for high efficiency gas‐phase oxidation of alcohols

Novel microfibrous‐structured silver catalysts were developed for gas‐phase selective oxidation of mono‐/aromatic‐/di‐alcohols. Sinter‐locked three‐dimensional microfibrous networks consisting of 5 vol % 8‐μm‐Ni (or 12‐μm‐SS‐316L) fibers and 95 vol % void volume were built up by the papermaking/sintering processes. Silver was then deposited onto the surface of the sinter‐locked fibers by incipient wetness impregnation method. At relatively low temperatures (e.g., 380°C), the microfibrous‐structured silver catalysts provided quite higher activity/selectivity compared to the electrolytic silver. The microfibrous Ag/Ni‐fiber offered much better low‐temperature activity than the Ag/SS‐fiber. The interaction at Ag particles and Ni‐fiber interface not only visibly increased the active/selective sites of Ag⁺ ions and Ag_nδ+ clusters but also significantly promoted their low‐temperature reducibility and ability for O₂ activation. In addition, the microfibrous structure provided a unique combination of large void volume, entirely open structure, high thermal conductivity and high permeability. © 2009 American Institute of Chemical Engineers AIChE J, 2010     

Ag and Si Codoped Phosphate Glasses: Plasmonic Nanocomposites with Enhanced UV Transparency

The use of silicon powder to produce plasmonic Ag nanocomposite phosphate glasses which also exhibit improved transparency in the ultraviolet (UV) is proposed. Ag₂O/Si codoped glasses were prepared in a barium‐phosphate matrix by a simple melt‐quench method in ambient atmosphere. The as‐prepared glasses exhibit enhanced UV transparency, whereby the surface plasmon resonance of Ag nanoparticles (NPs) is manifested for the glasses with higher Ag₂O contents. ³¹P nuclear magnetic resonance spectroscopy is consistent with the formation of P–O–Si bonds, thus suggesting their possible role on the improved UV light transmission. Consequently, a model was presented accounting for the influence of silicon on the polymerization of the phosphate network concomitant with the creation of highly reactive oxygen species. Further exploiting the proposed reactive species, a real‐time spectroscopic study of the plasmonic response of Ag NPs in Ag/Si codoped glass samples was carried out during an in situ thermal processing. The temperature dependence of the Ag particle precipitation was studied in the 400°C–430°C range, from which an Arrhenius‐type plot allowed for estimating the activation energy of the process at 3.42 (±0.38) eV. Ultimately, the vanishing of the luminescence ascribed to Ag⁺ ions was observed in a heat‐treated sample, consistent with the high reactivity acquired by the glass matrix. Silicon thus appears promising for producing UV transparent glasses for high‐performance optics and for the reduction of Ag⁺ ions to produce Ag nanocomposites valuable for photonic (nanoplasmonic) applications.     

Preparation and characterization of poly(vinyl alcohol) cryogel‐silver nanocomposites and evaluation of blood compatibility,cytotoxicity, and antimicrobial behaviors

In this investigation, cryogels composed of poly(vinyl alcohol) (PVA) were prepared by repeated freeze‐thaw method. The prepared cryogels served as templates for producing highly stable and uniformly distributed silver nanoparticles via in situ reduction of silver nitrate (AgNO₃) using alkaline formaldehyde solution as reducing agent. The structure of the PVA/Ag cryogel nanocomposites was characterized by a Fourier transform infrared and Raman spectroscopy. The morphologies of pure PVA cryogels and PVA/Ag nanocomposites were observed by a scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques. The SEM analysis suggested that cryogels show a well defined porous morphology whereas TEM micrographs revealed the presence of nearly spherical and well separated Ag nanoparticles with diameter about 100 nm. XRD results showed all relevant Bragg's reflections for crystal structure of silver nanoparticles. The amount of silver in cryogel nanocomposites and thermal stability were determined by inductively coupled plasma atomic emission spectrometry (ICP‐AES) and thermogravimetric analysis measurements. Mechanical properties of nanocomposites were observed in terms of tensile strength. The antibacterial studies of the synthesized nanosilver containing cryogels showed good antibacterial activity against both gram‐negative and gram‐positive bacteria. The prepared PVA/Ag nanocomposites were also investigated for swelling and deswelling behaviors. The results reveal that both the swelling and deswelling process depends on the chemical composition of the cryogel silver nanocomposites, number of freeze‐Thaw cycles and pH and temperature of the swelling medium. The biocompatibility of the prepared nanocomposites was judged by in vitro methods of percent hemolysis and protein (BSA) adsorption. POLYM. COMPOS., 36:1983–1997, 2015. © 2014 Society of Plastics Engineer