Characterization and physical properties of silver/PVA nano- composite (original) (raw)
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Fabrication and characterization of silver-polyvinyl alcohol nanocomposites
Chemistry of …, 2003
The influence of silver (Ag) nanoparticles on the properties of poly(vinyl alcohol) (PVA) was investigated. The nanocomposite was prepared by mixing a colloidal solution consisting of silver nanoparticles with a water solution of PVA in appropriate ratios. Composite films with different contents of inorganic phase were obtained after solvent evaporation. The contents of the inorganic phase in the nanocomposites were determined by using atomic absorption spectroscopy (AA) for silver, and were found to be 0.19, 0.33, and 0.73 wt %. Transmission electron microscopy (TEM) of the nanocomposite films revealed the presence of Ag particles with average diameter of 20 nm. Comparison of the thermal properties of the pure polymer and the nanocomposite films showed that the thermal stability is improved by about 40°C, and the glass transition temperature is shifted to a higher temperature up to 20°C for the highest content of the nanofiller. An increase in Young's modulus and strength of the nanocomposite was also observed with an increase in Ag content, indicating significant reinforcement of the matrix in the presence of nanoparticles. Stress relaxation measurements revealed reduced stability of the nanocomposite upon prolonged loading, compared to the pure PVA matrix.
Synthesis of Nanocomposites of Polyvinyl Alcohol with Silver Nanoparticles and Their Use
International Journal of Nanoscience, 2013
Composites of polyvinyl alcohol (PVA) containing silver nanoparticles were prepared using in situ synthesis of nanoparticles. Structure and properties of these composites were investigated using UV-Vis spectroscopy, XRD, DSC, SEM and AFM. The studies show that PVA can reduce the AgNO 3 to yield silver nanoparticles and in the process forms bonds with PVA chains. The anti-bacterial properties of these films were studied by qualitative as well as quantitative methods which gave the values of 98% for gram positive and 89% for gram negative bacteria.
Synthesis, mechanical andI-Vcharacteristics of Ag-PVA nanocomposite films
Physica Status Solidi (a), 2009
Hybrid polymer–inorganic nanocomposites have been prepared from an aqueous solution of polyvinyl alcohol (PVA) and silver nitrate (AgNO3). The silver nanoparticles have been generated in PVA matrix by reduction of silver ion with PVA molecules at 60–70 °C over a magnetic stirrer. X-ray diffraction studies, UV–visible analysis, transmission electron microscopy, scanning electron microscopy and current–voltage analysis were used to characterize the nanocomposite films prepared. The X-ray diffraction studies showed that silver metal is present in a face-centered cubic (fcc) crystal structure with average crystallite size 19 nm, which grows to 22 nm on annealing the film at 150 °C in air. This is in good agreement with the result obtained from TEM. The UV–visible spectrum shows a single peak at 433 nm, arising from the surface plasmon absorption of silver colloids. This result clearly indicates that silver nanoparticles are embedded in PVA. An improvement of mechanical properties (storage modulus) was also noticed due to a modification of PVA up to 0.5 wt% of silver content. The current–voltage (I–V) characteristics nanocomposite films obey Ohm's law and the current drawn increases with increasing Ag content in the films. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
Characterization of nano sized silver prepared in Polyvinyl Alcohol
Jurnal Nanosains & …, 2010
Silver nanostructures were prepared by chemical synthesis using polyvinyl alcohol (PVA) and the characteristic surface plasmon absorption of this nano-composite polymer was studied using UV-Vis absorption spectra. Samples were characterized using Scanning Electron Microscope (SEM), Energy Dispersive X-ray diffraction (EDX) and Transmission Electron Microscope (TEM). It is seen that truncated octahedral silver nanoplates has been formed with high intense plasmon absorption and it is the first report of truncated octahedral silver nanoplate using polyvinyl alcohol. It is found that the intensity of plasmon absorption depends not only on the density of the material but also on the shape of the nanostructures formed and also it is found that the weight percentage of silver has a control on deciding the shape of the particles in polyvinyl alcohol (PVA).
The effect of silver nanoparticles doped in PVA on the structural and optical properties of composite films is studied experimentally. Samples are PVA films of 0.14 mm thickness doped with different sizes and concentrations of silver nanoparticles. Structural properties are studied using X-ray diffraction and FTIR spectrum. Using the reflectance and transmittance of samples, the effect of doped nanoparticles and their concentration on optical parameters of PVA films include absorption coefficient, optical bandgap energy, complex refractive index, complex dielectric function, complex optical conductivity, and relaxation time is extracted and discussed. The dispersion of the refractive index of films in terms of the single oscillator Wemple-DiDomenico (WD) model is investigated and the dispersion parameters are calculated. Results show that by doping silver nanoparticles in PVA, number of Bragg's planes in the structure of polymer and its crystallinity are increased noticeably. Ag-O bonds are formed in the films and the bandgap energy of samples is decreased. Calculations based on WD model confirm that by doping nanoparticles, the anion strength of PVA as a dielectric medium is decreased.
Synthesis and Optical Characterization of Ag/PVA Nanocomposites Films
Journal of Al-Nahrain University Science, 2017
Silver-Poly vinyl alcohol Ag/ PVA nanocomposite films were prepared by casting method at room temperature with different amount of AgNO 3 solution (0.001, 0.0015, and 0.002ml). The prepared nanocomposites were characterized using UV-VIS spectrophotometer and the optical properties were investigated in the wavelength range 300-800 nm. The absorption peaks showed a shift towards higher wavelength with increasing AgNO 3 concentration while the energy band gap and absorption edges shifted towards lower energies with the increase of AgNO 3 concentration.
Thermal- and Sun-Promoted Generation of Silver Nanoparticles Embedded into Poly(vinyl alcohol) Films
Macromolecular Materials and Engineering, 2009
Nanocomposites based on poly(vinyl alcohol) and silver nanoparticles were efficiently prepared by sun-and thermal-promoted reduction processes. Uniaxial drawing of the Ag/PVA nanocomposites favoured the anisotropic distribution of silver particles, providing oriented films with polarisation-dependent tunable optical properties. These dichroic properties were more pronounced for nanocomposites produced by sun exposition, which provided more compact and interacting metal clusters. The results obtained suggest the nanocomposite films could find potential applications as colour polarising filters, radiation responsive polymeric objects and smart flexible films in packaging applications.
Preparation, Structure, and Properties of PVA–AgNPs Nanocomposites
Polymers
The aim of the work was to prepare a polymer matrix composite doped by silver nanoparticles and analyze the influence of silver nanoparticles (AgNPs) on polymers’ optical and toxic properties. Two different colloids of AgNPs were prepared by chemical reduction. The first colloid, a blue one, contains stable triangular nanoparticles (the mean size of the nanoparticles was ~75 nm). UV–vis spectrophotometry showed that the second colloid, a yellow colloid, was very unstable. Originally formed spherical particles (~11 nm in diameter) after 25 days changed into a mix of differently shaped nanoparticles (irregular, triangular, rod-like, spherical, decahedrons, etc.), and the dichroic effect was observed. Pre-prepared AgNPs were added into the PVA (poly(vinyl alcohol)) polymer matrix and PVA–AgNPs composites (poly(vinyl alcohol) doped by Ag nanoparticles) were prepared. PVA–AgNPs thin layers (by a spin-coating technique) and fibers (by electrospinning and dip-coating techniques) were prepa...
Silver-polyvinyl alcohol (Ag-PVA) nano composite dispersion have been synthesized by facile chemical reduction method. The film obtained from this dispersion shows to have particle size varying from 10-50 nm. This wide range of variation is supported by broadening of UV-Vis spectra also by the red shift in photoluminescence (PL) peak with the increase in excitation wave length. The observed effect may be assigned to contribution of particle size towards optical transition.
Gamma-irradiation assisted seeded growth of Ag nanoparticles within PVA matrix
Materials Chemistry and Physics, 2011
Polyvinyl alcohol (PVA)/Ag hybrid nanocomposites have been prepared from polymeric film of PVA and silver nitrate (AgNO 3 ). The silver nanoparticles were generated in PVA matrix by the reduction of silver ions with gamma-irradiation. UV-visible spectra showed a single peak at 422 nm, arising from the surface plasmon absorption of silver nanoparticles. The shifting of surface plasmon resonance peak after irradiation reveals that the gamma irradiation can be used as a size controlling agent for the preparation of silver nanoparticles embedded in PVA film. This result was in good agreement with the result obtained from TEM images. The TEM images showed the narrow size distribution of the obtained Ag nanoparticles with average particle size of 30 nm, which decreased to 17 nm with increasing irradiation dose. The X-ray diffraction analysis revealed that silver metal was present in face centered cubic (fcc) crystal structure. These results clearly indicate that monodispersed silver nanoparticles are embedded homogenously in PVA matrix.