Effects of Cu2+ Counter Ions on the Driving Performance of IPMC Artificial Muscle

Maolin Wang, Min Yu*, Qingsong He, Keju Ji

College of Astronautics, Nanjing University of Aeronautics and Astronautics, China

Ionic polymer metal composites (IPMCs), are a new kind of ionic electroactive polymer. The conductivity of surface electrodes that are electroless plated on both surfaces of the IPMCs plays an important role in the driving performance of IPMC artificial muscle. Owing to crack formation on the surface of platinum electrodes, occurring during bending of the IPMC, the surface resistance of the electrode increases, which greatly limits actuating performance. In this paper, we proposed a new method of dynamic self-repair electrodes by introducing Cu2+ into the IPMC basement membrane as counter ions. Therefore IPMC actuators with Cu2+ was carried out and the driving performance in the air was subsequently measured. In the morphology observation and resistance measurement of the IPMC electrodes, we found that many small copper particles scattered in the middle of cracks and the surface resistance decrease. Compared with conventional IPMC actuators containing Li+ counter ions, those containing Cu2+ counter ions exhibited larger displacement and bigger blocking force. In the C-V scan measurement, we proved the formation of copper particles was a dynamic process. Based on these measurements, it is concluded the presence of Cu2+ repaired the damaged electrodes and induced a lower electrodes resistance, thus leading to the driving performance improvement.