Effect of gamma-irradiation on (PEO/PVP)/Au nanocomposite: Materials for electrochemical and optical applications

Gold nanoparticles (Au NPs) have been successfully biosynthesized by Chenopodium murale (C. murale) leaf extract. Au NPs were incorporated within polyethylene oxide (PEO)/polyvinyl pyrrolidone (PVP) blend by casting method. Prepared samples were characterized before and after subjecting to successive gamma-irradiation doses (1, 2, 3, 4, 5 Mrad). XRD confirmed the semicrystalline nature of blend which was largely decreased after embedding Au NPs and subsequently through high irradiation doses. Before irradiation, FT-IR spectra revealed presence of main vibrational bands due to both PEO and PVP. After irradiation, FT-IR spectra indicated the existence of structural rearrangements in the polymeric matrix due to irradiation process. UV/vis spectra indicated presence of n-pi* transition results from single-bond in the backbone of blend and showed a visible band at 531 nm attributed to the surface plasmon resonance of Au NPs that is largely affected by irradiation dose. The values of optical parameters were enhanced due to embedding Au NPs and varied according to the irradiation dose. TEM images showed that particle size range was reduced from 1 to 34 nm for nanocomposite to 4-22 nm after exposure to gamma-radiations of 5 Mrad. TGA analysis showed an improvement for the thermal stability of nanocomposite sample after gamma-rays treatment. (C) 2016 Elsevier Ltd. All rights reserved.