Cholesteric Textures of Aqueous Hydroxypropylcellulose Solutions

Abstract

Liquid crystalline textures exhibited by aqueous solutions of hydroxypropylcellulose were investigated by video-enhanced contrast polarized light microscopy. For the first time in this particular system, typical cholesteric structures, such as oily streaks and fingerprint lines, were resolved in close detail by light microscopy. Biphasic separation was observed even in samples of concentration well above the critical value generally accepted for mesophase formation at room temperature (∼40% wt). The dependence of the helical pitch on polymer concentration was also studied, by Fourier transforming images of the cholesteric textures.