Surface constraints controlled structural dynamics of ferroelectric liquid crystals

The dielectric response of strongly surface anchored sample cells having various sample thicknesses of three ferroelectric liquid crystals (FLCs) has been studied and analyzed in the light of partial unwinding of helical structure at the interface of solid substrate and FLCs. Three FLCs (two conventional and one short pitch) have been selected based on their spontaneous polarization (P-s) and pitch values. Two conventional FLCs have the same pitch, but, different P-s values, whereas third FLC is short pitch having the same P-s as one of the conventional FLCs. The dielectric response of sample cells from thin to thick sample cell thicknesses has been studied by applying the low (100 mV) and high (1 V) amplitude of measuring voltages. In medium thickness range of 6-20 mu m, the partially unwound helical mode (p-UHM) process is very dominant, resulting into high dielectric permittivity. In thin and thick cells, no low frequency peak was observed at any amplitude of measuring voltage, which represents the p-UHM process, in any of the FLC materials. Electro-optical contrast is used for realization of the p-UHM which is significant for low power operation devices.