Enhancement of the electromechanical behaviour of IPMCs based on chitosan/polyaniline ion exchange membranes fabricated by freeze-drying
The electromechanical behavior of ionic polymer-metal composite (IPMC) based on a chitosan/polyaniline (CP) interpenetrating polymer network (IPN) is influenced by the internal structure of the CP ion exchange membrane. The freeze-drying method was found to be successful in improving the IPMC electromechanical properties. The effect of various pH (1, 4, 7, 10) on the equilibrium water content (EWC) and electromechanical response were investigated. From swelling ratio and differential scanning calorimetry (DSC) measurements, the freeze-dried membranes exhibited a higher swelling ratio and increased free water content. Electron beam lithography (EBL) was used to manufacture the IPMC metal electrodes. Experiments on the bending of IPMC samples in a direct current electric field showed that the freeze-dried samples had a faster and larger bending motion than non-freeze-dried samples.