Dilute-Solution Properties of Polystyrene in Θ-Solvent Media. II. An Analysis of Environmental Effects

Abstract

Intrinsic viscosity, light scattering, and associated dilute solution data for polystyrene in five Θ solvents are examined with the object of assessing the component contributions to unperturbed coil dimensions attributable to thermal and specific solvent effects. It is found that, if the latter environmental factors are treated as independently operative and if the temperature derivative of the second virial coefficient in the vicinity of Θ is taken as an index of the solvent effect, a basis for resolution of the perturbing contributions is provided. The same analysis applied to other published data for polystyrene:Θ-solvent pairs permits rational explanation of some heretofore anomolous variations of intrinsic viscosity [η]θ with temperature. Resolution of effects for a series of chemically related Θ solvents previously considered leads to a slightly larger value, +0.6×10−3, for the temperature coefficient of mean-square end-to-end distance d ln〈r02〉/dT. Equivalent chain parameters for the polymer in each of the five media are calculated and interpreted from the point of view of observed dilute-solution characteristics.