Electric deformation response of anion-exchange membrane/gold composites

In previous papers, actuation phenomena of solid polymer electrolyte membrane (SPM)/metal (M) composites which can be controlled by small electric signals were reported. The actuation response has been applied to various applications as electrically controllable actuators. The solid polymer electrolyte membranes used in the previous reports were cation-exchange type. In this study, the similar response of the anion-exchange membrane/metal composite has been investigated in order to clarify the response mechanism of the SPM/M composite. A chemical plating method of forming gold on the surfaces of the anion-exchange membrane is developed. The composite was found to bend to the cathode side. The specific displacement was proportional to the amount of charge accumulated in the electrode. The quantitative electrokinetic model of the electric mechanical response of the SPM/M composite was developed, which attributes the response to the stress induced by the water-drag associated with the movement of the counterion in the membrane, which is the same basis as the case of the cation-exchange membrane. The experimental results were successfully explained by using the model. (C) 2003 Elsevier Ltd. All rights reserved.