V. Tam Bui

Ionic conductivity of chitosan membranes

AbstractChitosan membranes with various degrees of deacetylation and different molecular weights (MW) were prepared by film casting withaqueous solutions of chitosan and acetic acid. Ultraviolet (UV) spectrometry and infrared (IR) spectrometry were used to determine thedegree of deacetylation (DDA) of chitosan. The viscosity–average MW of chitosan was measured in an aqueous solvent system of 0.25 MCH 3 COOH/0.25 M CH 3 COONa. The intrinsic ionic conductivities of the hydrated chitosan membranes were investigated using impedancespectroscopy. It was found that the intrinsic ionic conductivity was as high as 10 24 Scm 1 after hydration for 1 h. The tensile strength andbreaking elongation of the membranes were evaluated according to standard ASTM methods. The crystallinity and swelling ratio of themembranes were examined. A tentative mechanism for the ionic conductivity of chitosan membranes is also suggested.q 2002 Published by Elsevier Science Ltd. Keywords: Chitosan membrane; Hydration; Ionic conductivity