ABSTRACT
Hexanoyl chitosan that exhibited solubility in THF was prepared by acyl modification of chitosan. Atactic polystyrene was chosen to blend with hexanoyl chitosan. LiCF3SO3 was employed as the doping salt. Untreated and HNO3-treated TiO2 fillers were dispersed in hexanoyl chitosan-polystyrene-LiCF3SO3 electrolyte at 4 wt.% concentration. We observed better filler dispersion in the matrix for the acid treated system. The resulting composite electrolyte films were characterized for the electrical and tensile properties. Untreated TiO2 improved the electrolyte conductivity while HNO3-treated TiO2 decreased the conductivity. A model based on interaction between Lewis acid-base sites of TiO2 with ionic species of LiCF3SO3 has been proposed to understand the conductivity mechanism brought about by the fillers. The conductivity enhancement by untreated TiO2 is attributed to the increase in the number and mobility of Li+ cations. HNO3-treated TiO2 decreased the conductivity by decreasing the anionic contribution. An enhancement in the Young’s modulus and toughness was observed with the addition of TiO2 and greater enhancement is found for the treated TiO2. This is discussed using the percolation concept.
