Investigation of Optical and Electrical properties of Solid Polymer Electrolyte based on Natural polymer

Solid biopolymer electrolytes (SBEs) consisting of a natural blend that is leak-proof, biodegradable, and flexible are widely studied. In this study, an SBE composed of a fixed ratio of 50:50 of chitosan: polyvinylpyrrolidone (CS: PVP), and CS: PVP mixed with potassium iodide (KI) of different weight percentages of 7.5, 15, 22.5, 30, and 37.5 wt.% was prepared using the solution casting technique. The samples were characterized using UV-Vis spectrophotometry, Fourier transform infrared (FTIR), and AC conductivity. FTIR analysis confirmed the interaction between the polymer blend of CS: PVP and the potassium salt. The addition of KI was found to disrupt hydrogen bonding between the polymer chains, likely due to the polymer-salt interaction. Only one absorption peak was observed in the UV-Vis spectroscopy of the sample at around 315 nm. The conductivity increased as the KI wt.% increased, having a value of 3 × 10⁻⁴ S.cm⁻¹ at room temperature for the CS: PVP blend with 37.5 wt.% KI.