Experimental Investigation on Electrochemical Properties of Ionic Polymer–Metal Composite

Platinum has been used as an effective electrode material for ionic polymer– metal composite (IPMC) actuators. Realizing that platinum is a common catalyst for many electrochemical reactions; the platinum surface in IPMCs allows many components to be adsorbed. Therefore, under imposed electrical potentials, platinum electrodes used for IPMCs introduce complex electrochemical phenomena on the platinum–electrolyte interface. This study points out that the electrochemical characteristics of platinum are important in understanding the fundamental actuation mechanism of IPMCs. Electrochemical analyses, including voltammetry, AC impedance, and capacitance measurements, on IPMC samples are carried out in aqueous solutions. Such experimental results reveal the complex electrochemical behavior of IPMCs, including inductive behavior in higher frequencies than has originally been expected. The Mott-Schottky experiment is also performed to investigate the charge transfer and the possible adsorption mechanism associated with IPMCs. Seemingly, the equivalent circuit of IPMC follows a RLC circuit.