THE HYDRODYNAMIC SCALING MODEL FOR POLYMER DYNAMICS

Critical experiments constraining the range of physically acceptable models for polymer solution dynamics are discussed. The critical experiments determine the effect of matrix topology, probe topology, and matrix cross-linking on probe- and self-diffusion. A specific model for polymer motion in solution follows naturally, namely the hydrodynamic scaling model for polymer dynamics. Fundamental assumptions of the model (coil contraction, self-similarity, and the dominance of hydrodynamic forces) are described. Major predictions of the model are given and shown to compare favorably with experiment. There exist alternatives to hydrodynamic scaling, notably the reptation-entanglement pictures, which assert the dominance of topological interchain interactions over hydrodynamic forces. A wide variety of experimental evidence, discussed herein, supports the hydrodynamic scaling model and rejects reptation-scaling pictures.