Super-compliant metallic electrodes for Electroactive Polymer Actuators

Electroactive polymer (EAP) actuators are compliant capacitors, where a thin elastomer film is sandwiched between two compliant electrodes. When a high DC voltage is applied to the electrodes, the arising electrostatic pressure squeezes the elastomer film in thickness and thus the film expands in planar directions. They are very promising candidates for "artificial muscles" development. Dielectric elastomer transducers benefit of important advantages compared to other electro-mechanical actuators: high energy density, large and noise-free deformation capability and low cost materials. However, if EAP devices have to be cheap, they work at high voltage (> 1000 V) leading to need for expensive electronics. Such operating conditions preclude their use close to the human body. The electrode material is also a challenge, since clean and fast processes suited to miniaturization of EAP devices are still missing. To solve these drawbacks, we are developing a new fabrication process aiming at reducing the dielectric layer thickness down to <20 mu m and to increase the efficiency using highly conductive electrode materials deposited by magnetron sputtering. In this work, we show how we succeed in finding the conditions for deposition of compliant metallic thin films that are able to maintain high conductivity at more than 10% stretching. The films are characterized by X-Ray Diffraction, electrical conductivity measurements and Atomic Force Microscopy.