Electric-stimuli-responsive bending actuator based on sulfonated polyetherimide

In this study, based on the ionic exchangeable membrane of biocompatible sulfonated polyetherimide (SPEI), a novel electric-stimulus-responsive bending actuator was developed. The degree of sulfonation of SPEI was controlled with chlorosulfonic acid and was analyzed by using 1H nuclear magnetic resonance spectroscopy and thermogravimetric analysis. The SPEI membrane prepared by a solution casting method shows good electro-chemical properties of ion-exchange capacity, water uptake and proton conductivity required for a high-performance ionic polymer actuator. The SPEI ionic polymer–metal composite actuator, which was prepared by coating platinum layers on both sides of the membrane by an electroless plating process, shows good harmonic and step responses as an electro-active polymer.