Electro‐optical switching properties for measuring the parameters of a ferroelectric liquid crystal

Abstract

We present a description of the reorientation of the macroscopic polarization P S under a switching field in a ferroelectric liquid crystal assuming the direction of P S is spatially uniform but time-dependent throughout the sample. The driving torques are then the linear ferroelectric coupling and the quadratic dielectric torques. If the theory is correct, some of the important parameters of a FLC may be determined in a single experiment, such as the spontaneous polarization P S , the switching delay t m , the switching time t, the orientational viscosity g and the dielectric anisotropy e a . The measurements are performed using new compound, as a function of temperature with different field strengths and sample thicknesses. The experiment appears to be poorly fit by the so-called 'rigid' hypothesis leading to the conclusion that the switching of polarization is not uniform but rather starts locally from orientational defects and propagates quickly throughout the sample. This reinforces the view that the driving torque equation is nothing but the Sine-Gordon equation reminiscent of soliton propagation.

Reduction of optical response time for fluorescent dye doped ferroelectric liquid crystal

“…5. The behavior of the spontaneous polarization with variation in the temperature is the same as those reported for other FLCs [20][21][22][23] i.e. the magnitude of the spontaneous polarization is continuously decreasing and it vanishes at the SmC*-SmA phase transition point or near this phase transition point.…”

Analogue-driven bistable ferroelectric liquid crystals

“…We assume that all of the electrical energy supplied by the polarization current is converted into mechanical work. This gives a relation between I pol and the rotation speed of the molecule [22]:…”

Quantum Dot Doped Ferroelectric Liquid Crystal System: Investigation of Electro-Optical Parameters and Relaxation Behavior

“…The tilt angle is half of the angle between the two extinction positions [13]. To measure the spontaneous polarization of the pure and the doped system, polarization reversal current method has been used [14][15][16]. The detailed experimental arrangement for this measurement has already been reported by our group [17].…”