Chain interdiffusion: Macromolecules between rouse and de gennes

The motion of whole chains or of parts thereof fundamentally influences the rheological and the mechanical properties of liquid and solid polymers. In this contribution different forms of interaction between a moving chain and a moving environment are discussed. Depending on the experimental and on the molecular time scales (where the latter is essentially fixed by molecular weight) a macromolecule does surprisingly different things: swim as a coil through a highly viscous environment (Rouse), wind its way in a snake-like fashion through an almost solid matrix (de Gennes), become highly extended and loaded up to breakage or even break while maintaining its coiled conformation. Interdiffusion and extensional flow experiments have helped to elucidate some of the principal reactions of a macromolecule to mechanical stress.