Hydroxyapatite-imidazole-polymer composite films as a proton conductor under no humidified condition

Hydroxyapatite (Ca₁₀(PO₄)₆(OH)₂, HAp)-imidazole (Im)-poly(vinylidene fluoride) (PVdF) composite films were prepared by casting the HAp dispersed solution that included Im and PVdF. Their conducting behaviors under no humidified condition and various temperatures were investigated. Two kinds of HAp (a-HAp and n-HAp) with different particle size were used. The average particle size of a-HAp was 1.25 pm in diameter and that of n-HAp was 0.61 pm in diameter. The conductivity for a-HAp-Im-PVdF (1:2:5, by weight) film at 120°C was 8.4 μS cm⁻¹ and that for n-HAp-Im-PVdF (1:2:5, by weight) was 298 μS cm⁻¹. The particle size of HAp and the amount of Im and HAp in the films affected their conducting behavior and their mechanical properties.