OPTIMIZATION OF PYROELECTRICITY IN THE SMECTIC-C-ASTERISK PHASE OF A LIQUID-CRYSTALLINE TERPOLYMER

The dynamic pyroelectric response in the smectic-C (SmC*) phase of a novel class of polysiloxane terpolymers is reported. In these terpolym ers methyl groups and two distinct types of mesogenic side chains are attached to the siloxane backbone. Our investigations reveal that the magnitude and temperature dependence of the pyroelectric signal, as we ll as the temperature range of the SmC phase, can be controlled by va rying the relative side-chain composition. This permits optimization o f the pyroelectric properties over a temperature range extending to su bambient. Specifically, the pyroelectric coefficient p can be made ver y nearly temperature independent, and the ratio p/epsilon' extremely h igh, making these materials suitable for uncooled infrared detectors. (C) 1996 American Institute of Physics.