MOLECULAR-WEIGHT AND TEMPERATURE-DEPENDENCE OF POLYMER DIMENSIONS IN SOLUTION

The molecular weight (Mw) and temperature (T) dependence of the radius of gyration (RG) and hydrodynamic radius (RH) of a polymer in a dilute solution are investigated. The theoretical predictions are compared with experimental results on polystyrene in various solvents as functions of Mw and T. It is found that the existing data fall in a region of values where RH cannot be represented by a simple power law RH ~ Nv, whereas most of the data on Rq satisfy RG ~ Nv. It is concluded that a power law fit to data would yield v < v in this region, even though the theory predicts v = v in the asymptotic region. The quantitative aspects of the blob theory are also discussed and compared in some cases to the modified Flory theory. © 1979, American Chemical Society. All rights reserved.