Influence of Time Dependent Factors To The Phases and Poisson's Ratio of Cholesteryl Ester liquid crystals

Abstract

Liquid crystal based biosensors detect physical restructuring of cells via changes in the birefringence property or orientation order of the liquid crystal molecules. The strain induced in the liquid crystal molecules is closely associated with the liquid crystalline phases and Poisson’s ratio of the liquid crystals. Cholesteryl ester liquid crystals (CELC) and CELC based lyotropic liquid crystals (LLC) that were regarded as viscoelastic materials are subjected to time-dependent factors (a fluidic environment, incubation time, and temperature). The effects of these factors, qualitatively and quantitatively, were investigated by using cross-polarising microscopy and a uniaxial micro-tensile technique. More lyotropic phases were observed in the liquid crystals as the incubation time in cell culture media was increased. Poisson’s ratio of approximately 0.58 and 0.6 were determined for CELC and LLC, respectively, at room (25 oC) and incubation (37 oC) temperatures over a period of 3 days.