CHAIN ARCHITECTURE IN THE HYDRODYNAMIC SCALING PICTURE FOR POLYMER DYNAMICS

The hydrodynamic scaling picture of polymer dynamics is extended to treat the consequences of chain architecture on tracer diffusion by linear and star polymers in a matrix of linear polymers. From hydrodynamic scaling, one clearly predicts: (i) whereas in comparing linear and many-armed star polymers of equal total molecular weight, a given large concentration of matrix polymer is modestly more effective (smaller D/Do) at retarding a linear polymer than at retarding a star polymer; (ii) with linear and star polymers of equal arm molecular weight, a large concentration of matrix polymer is far more effective at retarding a star than at retarding a linear polymer. Contrary to the claims of their authors, recent experiments of Lodge, Wheeler, et al. (Macromolecules 1989, 23, 3409) on tracer diffusion of linear and star polystyrenes in poly(vinyl methyl ether) matrices are consistent with predictions of the hydrodynamic scaling model. © 1990, American Chemical Society. All rights reserved.