INTRINSIC-VISCOSITY AND FRICTION COEFFICIENT OF POLYMER-MOLECULES IN SOLUTION - POROUS SPHERE MODEL

The intrinsic viscosity left bracket eta right bracket and the translational friction coefficient f of polymer molecules in solution are calculated on the basis of the porous sphere model. The only information needed to predict left bracket eta right bracket 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.″ The influence of solvent quality is more complex than is suggested by the experimentally verified Flory-Fox relation for left bracket eta right bracket ; 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 at the center. The connection between the present treatment and the microscopic theory of Kirkwood and Riseman is investigated.