Polarization in free standing chiral and nonchiral smectic films

There is no fundamental reason that nonchiral liquid crystals should not be ferroelectric. In this paper nonchiral flexoelectric effects (particularly leading to the specific orientation phenomena for smectic films in electric fields) are investigated in freely suspended films. Optical reflectivity measurements are presented for the region near the smectic-C^*-smectic-A and smectic-C-smectic-A phase transitions. Temperature dependences of the tilt angle are determined for two kinds of smectic structures where polarization is either perpendicular or parallel to the tilt plane.