ANTIFERROELECTRIC BEHAVIOR OF ACHIRAL MESOGENIC POLYMER MIXTURES

X-ray structure determination and pyroelectric and piezoelectric measu rements have been carried out on mesogenic mixtures composed of achira l side chain polymers and their monomers. Certain mixtures show antife rroelectric polarization hysteresis loops in the mesophase which was s hown to be a bilayered smectic C, while the two components of the mixt ures taken alone show no antiferroelectricity. The results obtained on the polymer-monomer mixtures are interpreted in terms of the smectic C structure with alternating tilt which, from a symmetry viewpoint, is allowed to be antiferroelectric. The antiferroelectric mixtures, on b eing cooled to the glassy state under a d.c. electric field applied, r eveal high pyroelectric coefficients with prospects for application as IR detectors.