Spontaneous electrical current in P(VDF/TrFE) copolymer

Short-circuit electrical currents were observed in 60:40 mol% P(VDF/TrFE) copolymers above 80/spl deg/C, temperature in which this polymer undergoes a structural ferro-to-paraelectric phase transition. The signal of this current was inverted when the sample is rotated so that the electrodes had their positions exchanged. Different combinations of metallic materials (aluminium, copper, nickel, and gold) were used as electrodes in metal(1)-polymer-metal(2) structures. Voltage signals were also detected in paraelectric samples, whose signal was equally dependent on the electrode combinations. This phenomenon is probably due to an electromotive force arising from different interfacial potential on both metal-sample interfaces.