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

Abstract

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.

Keywords:

• antiferroelectric liquid crystal
• dielectric spectroscopy
• V-shaped switching
• ferrielectric phase
• orthoconic liquid crystal