Dielectric relaxation spectroscopy and electro-optical studies of a new, partially fluorinated orthoconic antiferroelectric liquid crystal material exhibiting V-shaped switching

摘要

In this paper we report the results from detailed electro-optical and dielectric studies in various antiferroelectric and ferroelectric phases of an orthoconic antiferroelectric liquid crystal (OAFLC) material. The material possesses high tilt and high spontaneous polarisation. Such an OAFLC, because of its high tilt, provides an excellent dark state. The material exhibits V-shaped switching in the SmC* phase. Dielectric studies reveal the existence of another phase during heating in the range between 78.6 and 92°C which did not appear in the DSC curve and in polarising microscopy. This phase has been identified as the SmC_γ* phase and is extremely sensitive with respect to the cell conditions, aligning material, purity, etc. Three dielectric modes have been assigned in the above-mentioned temperature range and their origins are discussed.