Hydrodynamic constants and frictional properties of polystyrene in dilute solution

Experimental data from hydrodynamic measurements on eleven standard polystyrene samples in a poor and a good solvent (cyclohexane at theta-temperature 34,5°C, toluene at 25°C) are analyzed in terms of the two-parameter theory of the hydrodynamic properties of random coils. The discussion is focussed on the expansion factors of hydrodynamic radii α_f and α_μ, evaluated from the translation friction coefficients and the intrinsic viscosity, and on the hydrodynamic-interaction parameters P and Φ. The expansion factors α_f and α_η are shown to assume nearly equal values (at 1,15 ≤α_η ≤ 1,5). That implies that the dependences on coil expansion must be very similar for P and Φ^1/3. The value of the P parameter in the unperturbed state (i.e. P₀) is shown to be close to that recently calculated by Zimm and to be significantly higher than the results of previous theoretical calculations.