Molar conductivity and ion transport behavior of Kappa-carrageenan (κ-car) - liclo₄ Biopolymer Electrolytes at varying temperatures

The limiting molar conductivity (Λo) and ion transport behavior of a kappa-carrageenan (κ-car) and lithium perchlorate (LiClO4) in aqueous medium biopolymer electrolyte system at various temperatures (25 °C–50 °C) and polymer concentration, Cpoly (0.001–0.003 g cm-3) is measured for a range of salt concentration (1.000 × 10-4–4.702 x 10–8 mol cm–3) using simple AC conductivity meter that couple with its electrode. ohlrausch’s equation determines the Λo value of each system. It’s noted that the most significant Λo result in this study was observed in the ystem with the lowest polymer concentration at the highest temperature tested. This indicates that at infinite dilution, where ionion interactions are minimal, ionic species exhibit maximum mobility. Λo is strongly influenced by both temperature and polymer concentration. As temperature increases, Λo increases due to enhanced ion mobility and reduced viscosity of the polymer matrix, which facilitates free movement of charge carriers. Higher temperatures also promote better salt dissociation, reducing ion-pair formation and contributing to a higher concentration of free-moving ions. Conversely, increasing polymer concentration tends to decrease Λo. This is because a more concentrated polymer network increases viscosity and provides more binding or coordinating sites (e.g., from sulphate groups in κ-car) that can interact with Li+ or ClO4 - ions. These interactions can lead to stronger ion-polymer coordination or even ion-ion association, thus limiting the number of free ions available to conduct charges. Enhanced polymer-salt interactions in the κ-car/LiClO4 system are expected to boost ionic conductivity and temperature response. The activation energy (Ea) of the electrolyte system is calculated after the Arrhenius equation. The findings contribute to the advancement of understanding eco-friendly electrolyte systems for more advanced applications.