Intrinsic Viscosity and Friction Coefficient of Polymer Molecules in Solution: Porous Sphere Model

The intrinsic viscosity [q] and the translational friction coefficientf of polymer molecules in solution are calculated on the basis of the porous sphere model. The only information needed to predict [q] and f is the polymer molecular weight, the radius of gyration in the solvent, and the permeability as a function of position in the “porous sphere.” For systems for which this information is available there is satisfactory agreement between predicted and directly measured values of [q] and f. No adjustment of parameters is required. The influence of solvent quality is more complex than is suggested by the experimentally verified Flory-Fox relation for [?I; the simple form of this relation stems from the fact that two quite large effects of solvent quality approximately compensate each other. The complete flow pattern of the solvent around and through the polymer coil can be calculated. Contrary to what is usually believed the solvent flow in the polymer coil is not “effectively blocked”, even a t the center. The connection between the present treatment and the microscopic theory of Kirkwood and Riseman is investigated.