PIEZOELECTRIC AND PYROELECTRIC PROPERTIES OF NEW POLYSILOXANE SMECTICC-ASTERISK ELASTOMERS

We investigated the pyroelectric and piezoelectric effects of new smec tic C liquid crystalline elastomers. The materials are made up of a f lexible polysiloxane backbone bearing chiral mesogenic side groups and are cross-linked via alkylene chains. The polar structure of the meso phase is evidenced by the observation of piezoelectric and pyroelectri c effects. Integration of the pyroelectric coefficient over the whole smectic C stability range allows the determination of the spontaneous polarization (P-s = 3-6 nC/cm(2)). Due to the rubber elasticity, thes e materials exhibit a high piezoelectric response. The piezosignal at room temperature does not vanish after annealing at temperatures even much higher than the Curie point. The piezoelectric coefficient d(31) ranges from 0.5 pC/N for non-poled samples to 2.5 pC/N after applicati on of a poling field.