Surface resistance experiments with IPMC sensors and actuators

This paper describes experiments with the surface resistance of IPMC actuators and sensors. We measure the surface resistance of samples working as sensors or as a voltage driven actuators, as well as when insulated. The results show that in all cases the surface resistance of a sample is highly correlated to material curvature. Based on these observations we present an equivalent circuit, with variable resistors representing surface resistance, that models IPMC materials. Our simulations with SPICE show that the equivalent circuit closely models the actual behaviour of IPMC sensors and actuators. We show that since the IPMC model works as a delay line with changing resistors, the curvature of the IPMC sample at a given point depends on the surface resistance. This, in turn, affects further bending of the sample. The modified equivalent circuit also explains the hysteresis of IPMC actuators as the signals along the surface are delayed.