Molecular weight distributions from light scattering studies of polystyrene solutions during phase separation

Abstract Phase separations, brought about by cooling, of very dilute solutions of polystyrenes in a θ-solvent (methylcyclohexane) have been studied using a light scattering instrument. Molecular weight distributions of unfractionated polystyrene samples are presented, evaluated from the experimental data. Two methods of evaluation are described and compared: the conventional method led to poor results, whereas a new method, devised from the consideration of experimental and theoretical evidence, resulted in more accurate estimates of the mol. wt. distributions of the polymer samples.