Isha Saini; Annu Sharma; Naveneet Chandak; Sanjeev Aggarwal; Pawan K. Sharma
Abstract
Silver (Ag) nanoparticles play a significant role in nanomaterials science and technology due to many peculiarities. One of the main characteristic of Ag nanoparticles is the occurrence of surface plasmon resonance (SPR) due to the collective oscillation of free electrons in visible region. Due to this ...
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Silver (Ag) nanoparticles play a significant role in nanomaterials science and technology due to many peculiarities. One of the main characteristic of Ag nanoparticles is the occurrence of surface plasmon resonance (SPR) due to the collective oscillation of free electrons in visible region. Due to this distinctive feature Ag nanoparticles have numerous applications such as in catalysis, surface enhanced Raman spectroscopy, photonics, solar cells etc. In the present work, no additional stabilizing agent has been used. The characteristic SPR peak appears at around 405 nm in UV-Visible absorption spectra of PVA-Ag nanocomposite films, thereby confirming the nanocomposite formation. The synthesized nanocomposite films were structurally characterized using fourier transform infrared (FTIR) and Raman spectroscopy. FTIR spectra of PVA-Ag nanocomposite film indicates that PVA matrix is modified by Ag nanoparticles which is in agreement with the results obtained using Raman spectroscopy. TEM as well as FE-SEM micrographs reveal that Ag nanoparticles are mostly spherical in shape. The knoop microhardness number of the nanocomposites was found to increase from 2.4 Kgf/mm2 for PVA to 12.1 kgf/mm2 for PVA-Ag nanocomposite film loaded with 0.062 wt% Ag nanoparticles. Copyright © 2018 VBRI Press.
Meena .; Annu Sharma; Sanjeev Aggarwal; Pawan K. Sharma
Abstract
Bio-degradable polymers such as starch, chitosan, cellulose etc which are extracted from renewable resources are attracting increasing interest in the recent years due to their environmentally friendly nature, low cost and high availability. In the present work, synthesis of colloidal silver nanoparticles ...
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Bio-degradable polymers such as starch, chitosan, cellulose etc which are extracted from renewable resources are attracting increasing interest in the recent years due to their environmentally friendly nature, low cost and high availability. In the present work, synthesis of colloidal silver nanoparticles and subsequently Ag-starch nanocomposite films were carried out via a green process. For synthesis of Ag nanoparticles water, soluble starch and fructose have been used as solvent, reducing agent and stabilizing agent respectively. The effect of varying concentration of colloidal Ag nanoparticles on the optical and structural properties of starch was investigated. The structural analysis of the nanocomposites was carried out using Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM). Size of the Ag nanoparticles from TEM micrograph comes out to be 10.75 ± 0.8 nm in the starch matrix. UV-visible absorption was further utilized to ascertain various optical constants like optical energy gap, Urbach’s energy, optical conductivity etc. The optical energy gap of starch decreases from 4.08 eV to 2.21 eV for Ag-starch nanocomposite film containing 0.50 wt% of Ag nanoparticles and the Urbach’s energy increases from 0.77 eV to 1.37 eV. Copyright © 2017 VBRI Press.