Isotropic-Liquid Crystal Phase Equilibrium in Semiflexible Polymer Solutions: Application of Scaled Particle Theory

Abstract

The scaled particle theory of Cotter for straight spherocylinders was extended to semiflexible polymer solutions following Khokhlov and Semenov's procedure to calculate the isotropic-liquid crystal phase boundary concentrations and osmotic pressure of the solution, with the diameter d and persistence length q of the polymer as parameters. The calculated phase boundary concentrations and osmotic pressure were compared favorably with experimental data for aqueous schizophyllan (a triple helical polysaccharide) and poly(hexyl isocyanate) in toluene and dichloromethane when use was made of the experimental q values and the d values rather close to those obtained from the partial specific volume of the polymer. Thus the thermodynamic behavior of the systems investigated was explained essentially in terms of the hard-core potential.