STUDIES ON CRITICAL CONCENTRATION OF LIQUID CRYSTALLINE ETHYLCELLULOSE

Critical concentrations of lyotropic liquid crystalline ethylcellulose in more than tensolvents were determined using both Abbe refractometer and polarized microscopy. Criti-cal concentration C_(crit) of forming liquid crystal phase decreased with increasing solubilityparameter δ of solvent until approaching the δ of polymer. Although the alcohols usedas solvents had the same variation rule, the critical concentration values of their solutionswere much higher, due to their excessive large hydrogen bond component of δ. The experi-ments of using mixed solvents which showed good linear relation between C_(crit) and δ alsoproved this rule. A technique of Transmission Optical Analysis was first used to estimatethe concentration dependence of critical phase transition temperature T_(crit) of EC, and aT-C phase diagram could be drawn.

STUDIES ON CRITICAL CONCENTRATION OF LIQUID CRYSTALLINE ETHYLCELLULOSE*

 Critical concentrations of lyotropic liquid crystalline ethylcellulose in more than tensolvents were determined using both Abbe refractometer and polarized microscopy. Criti-cal concentration C_crit of forming liquid crystal phase decreased with increasing solubilityparameter δ of solvent until approaching the δ of polymer. Although the alcohols usedas solvents had the same variation rule, the critical concentration values of their solutionswere much higher, due to their excessive large hydrogen bond component of δ.The experiments of using mixes solvents which showed good linear relation between C_crit and δalso proved this rule.A technique of Transmission Optical Anaysis was first used to estimate the concentration dependence of critical phase transition temperature T_critof EC,and a T-C phase diagram could be drawn.