Chitosan-PEG-NaI based bio-polymer electrolytes: structural, thermal and ion dynamics studies

BPE films based on [Chitosan (CS)-PEG]-NaI were prepared using solution cast technique. The prepared electrolyte films were subjected to thermal, structure and conductivity studies using TGA, XRD, ATR-FTIR and AC impedance spectroscopic techniques. The thermal gravimetric analysis (TGA) reveals that the CS and [CS-PEG]-NaI based films decomposes in multi step. Onset decomposition temperature (T d,onset ) also decreases with increasing NaI content in CS-PEG based films. The [CS-PEG]-NaI based films are thermally stable upto ∼220.2 °C. XRD result shows that CS has semi-crystalline in nature having its characteristic peak appeared at 2 θ ∼ 23.1°. The % degree of crystallinity (Xc) decreases with increasing NaI content in CS-PEG based films. ATR-FTIR study confirms the interaction between bio-polymer, CS with PEG and NaI. The sample containing 40 wt%NaI shows dc conductivity value ∼7.25 × 10 −4 Scm −1 at 30 °C. The values of frequency exponent s for BPE films were found to be 0.68 to 0.22. Scaling of ac conductivity with respect to NaI concentration has been performed. Mobility ( μ ) and total number density of charge carriers ( N ) were estimated from loss tangent spectra.