POLYMER DYNAMICS IN SOLUTION - UNIVERSAL PROPERTIES VS INDIVIDUAL BEHAVIOR IN A UNIFIED APPROACH

The main factors affecting the dynamics of polymer chains in dilute so lution are reviewed. We consider both the collective properties of the chain that follow relatively simple universal laws and the local prop erties related to the chain stereochemistry. Good-solvent expansion an d hydrodynamic interaction are discussed for chains of different archi tecture, in particular linear and regular star polymers, starting from the usual Rouse-Zimm approach. We also include in the dynamic equatio ns the effect of the local chain stiffness, arising from (i) the equil ibrium configurational properties of the chain and (ii) the energy bar riers to skeletal rotations hindering the propagation of conformationa l rearrangements along the chain backbone. The quantities taken into c onsideration are the intrinsic viscosity and the hydrodynamic radius, compared with the radius of gyration, as well as the complex modulus m easured under an oscillating shear deformation, and the dynamic struct ure factor measured through quasielastic scattering. As an example of non-equilibrium behaviour, we discuss a theoretical investigation of t he kinetics of chain contraction to a compact globular state following a sudden change in solvent quality.