RANGE OF VALIDITY OF THE HYDRODYNAMIC SCALING MODEL

Literature data on the zero-shear viscosity eta and chain self-diffusion coefficient D, of solutions of high-molecular-weight polymers are used to locate boundaries between solutionlike and meltlike behavior of these transport coefficients. The boundaries are apparent as a change in the concentration dependence of eta and D(s), eta(c) and D(s)(c) having a stretched-exponential concentration dependence under solutionlike conditions and a power-law concentration dependence under meltlike conditions. In general, a transition to meltlike behavior becomes apparent only if eta/eta0 is > 10(3) (eta0 being the solvent viscosity) or if D/D0 much less than 10(-3) (D0 being the zero-concentration limit of D(s)), though cases of transitions at smaller eta/eta0 or larger D/D0 are identified.