Electroactive polymers (EAP) characterization methods

Electroactive polymers (EAP) are emerging as a new class of actuation materials bring considered in a wide range of applications. Their large electrically induced strains (bending or extensional), low density,ease of processing, and mechanical flexibility offer advantages over traditional electroactive materials. However, before these materials can be properly exploited, their electrical and mechanical properties must be properly quantified. Two general types of EAP can be identified including wet (hydrated) and dry materials. The first type requires relatively low voltages (<10V) to achieve large bending deflections (more than 90 degrees). This class usually needs to be hydrated and electrochemical reactions may occur. The second type of EAP involves electrostrictive and/or Maxwell stresses. These types of materials require large electric fields (>100MV/m) to achieve large extensional deformation (>4%). Some of the difficulties that are involved with the characterization of the properties of EAP include nonlinearity, large compliance (large mismatch with metal electrodes), non-homogeneity formed during processing, etc. In order for this technology to fully mature, the authors are developing characterization techniques to quantify their electroactive responses and material properties. This paper focuses on a new testing procedure for bending EAP. Results for ion exchange Flemion membranes are presented.