Modifications induced in the optical properties of starch by embedded Ag nanoparticles
Meena, Annu Sharma, Sanjeev Aggarwal, Pawan K. Sharma
Volume 2, Issue 10, Page 662-666, Year 2017 | DOI: 10.5185/amp.2017/813
Keywords: Nanoparticle, nanocomposite, starch, optical energy gap, Urbach’s energy.
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 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.