Pyroelectric properties of polymer dispersed ferroelectric liquid crystals

Abstract

A polymer dispersed ferroelectric liquid crystal (PDFLC) is a novel material combining properties of a polymer (flexibility, elasticity) and ferroelectric liquid crystal (low voltage, fast electro-optical switching). Another interesting field of application of PDFLC is the detection of low intensity radiation using the pyroelectric response of the material. A PDFLC material containing a ferroelectric liquid crystal (FLC) with very high spontaneous polarization (close to 200 nC/cm2 at room temperature) was prepared to study its pyroelectric properties. The matrix was pure polymer poly-butadiene-styrene which can be mixed with liquid crystals in volatile solvents. The pyroelectric response and the spontaneous polarization were measured over a wide temperature range of the smectic C* phase and compared with the corresponding quantities of the pure FLC. Figures of merit of pyroelectric PDFLC films were estimated and compared with those known for conventional ferroelectrics. © 1998 American Institute of Physics.