Reducing leakage current and dielectric losses of electroactive polymers through electro-annealing for high-voltage actuation

Abstract

Electroactive polymers (EAPs) such as P(VDF-TrFE-CTFE) are very promising in the field of flexible sensors and actuators. Their advantages in smart electrical devices are due to their low cost, elastic properties, low density, and ability to be manufactured into various shapes and thicknesses. In earlier years, terpolymer P(VDF-TrFE-CTFE) attracted a lot of research due to its relaxor-ferroelectric property that exhibits high electrostriction phenomena. While widely used in flexible actuation, this class of material is still limited by the high electric fields required (≥30 V μm⁻¹) to achieve sufficient strain levels (>2%). This inevitably leads to high levels of leakage current and thus a short lifetime. This paper proposes a new approach based on electro-annealing thermal treatment for a pure terpolymer P(VDF-TrFE-CTFE) matrix in order to limit the conduction mechanisms. This in turn reduces the dielectric losses at a high level of electric fields. The experimental results demonstrate that a huge decrease in leakage current of 80% is achieved for a wide range of electric fields (i.e. up to 90 V μm⁻¹) with a 4-fold extension in time-to-breakdown at high voltage excitations of 40 V μm⁻¹.