A piezoelectric actuator having a plurality of plates of a piezoelectric material whose polarization direction runs perpendicularly to the plate plane, and which are stacked one over another in their polarization direction. According to the invention, the first layer contains a wear-resistant and electrically conductive ionomer polyelectrolyte and the second layer is electrically conductive. The first collector region has a first collector voltage and a first voltage threshold. One embodiment employs an Orthogonal Frequency Divisional Multiplex waveform for the synchronized broadcast. The thermal barrier includes at least two areas of elastic material, each elastic area having directional stretch qualities such that each elastic area has greater elasticity in an associated particular direction than in other directions, and wherein said particular directions for said at least two elastic areas are not parallel.