Degradation Mechanism of Ionic Polymer Actuators Containing Ionic Liquids as a Mixed Solvent

摘要

The degradation mechanism of ionic polymer metal composites (IPMCs) containing hydrophobic ionic liquids has been investigated. The ionic liquid was mixed with ethylene glycol in order to obtain high solvent uptake. The actuation response of the IPMCs with the mixed solvent was faster than that with only ethylene glycol. During the actuation durability tests under an AC square wave input, the IPMCs suffered from liquid squeezing-out problem, resulting in lower solvent concentration inside the IPMCs and hence poor actuation response. The degradation development of the IPMCs was influenced by the applied AC frequency. The tip displacement and the electric current were used to study the degradation development under AC electric field. Tin layer of polyurethane was applied on the IPMC surface to minimize the squeezing problems. The degradation was not significant observed after being subjected to 3V square wave input for more than 20 hours. However, the conductivity of the coated IPMCs was lower than that of the uncoated ones.