CHOLESTERIC TEXTURES OF AQUEOUS HYDROXYPROPYLCELLULOSE SOLUTIONS

Liquid crystalline textures exhibited by aqueous solutions of hydroxyp ropylcellulose were investigated by video-enhanced contrast polarized light microscopy. For the first time in this particular system, typica l 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 (similar to 40% wt). The dependence of the helical pitch on polymer co ncentration was also studied, by Fourier transforming images of the ch olesteric textures.