Hydrodynamic interaction effects on intrinsic viscosity of perturbed chains: Experimental results for polystyrene

Experimental measurements of intrinsic viscosity and radii of gyration of monodisperse samples of polystyrene of molecular weights 2.33 X 10⁵, 4.11 X 10⁵, 6.70 X 10⁵, and 2.3 X 10⁶ dissolved in the homologous series of 1-chloroparaffins from butane to undecane are reported. The dependence of the viscosity expansion coefficient α_η on the expansion factor α_s for the radius of gyration is discussed in the light of the results obtained by an expansion of the Fixman theory for perturbed chains to include partial draining. These results give support to the finite chain effect on the hydrodynamics of expanded coils in the usual range of molecular weight. The exponent a in the relation α³_η = α^a_s depends on molecular weight and agrees with recent nondraining theoretical calculation for exceedingly high polymers.