Conducting polymer actuator utilizing novel planar patterned flexible supporting electrode

Abstract

A number of architectures have been employed to realize the linear contraction desired of a large scale conducting polymer artificial muscle, with each having merits and problems. Bulk polymer actuators with no supporting electrode structure, coil- or spring-type designs, and thin linear actuators with pliant metal or semi-metallic surface electrodes have all found moderate success. For the purpose of scalable, highly reactive artificial muscles, it is proposed that a design of several thin, well coupled and highly conductive linear actuators will allow rapid charging, ion transport, and actuation. Here we present a novel electrode design utilizing conducting polymers, incorporating recent work on electrode materials, solvents, and electrolyte. The soft supporting electrode is a highly flexible design made from metal foil patterned by lithographic techniques to allow a wide range of deformations and no hindrance to linear motion by the supporting metal electrode. The design is such that the electrode metal maintains excellent electrical coupling with the actuator material throughout the range of motions. The actuator is based on the well-characterized conducting polymer polypyrrole. Other merits of this actuator lie in the inexpensive material design, ease of manufacture, and modular potential to create multi-actuator devices for high stress applications. In order to overcome adhesion and conduction problems exhibited by the low-cost materials, several surface treatments were evaluated. In the course of development, stainless steel samples coated with platinum and titanium oxide were evaluated with an adhesion test. In an attempt to improve overall actuator performance, films were grown on steel and glassy carbon substrates in organic and ionic liquid solvents and actuated in organic and ionic liquid based solutions.