Dynamics of polymer chains from expanded coils to the collapsed state

Abstract

Static and dynamic laser light scattering and viscometry have been used to study the dynamics and structure of coil-to-globule transition. With the prism-cell laser light scattering spectrometer, very small scattering angles of the order of 3^o could be reached which enabled us to determine the pure translational motion of large polymer chains. The contraction size of a polymer chain during the collapse process has been measured in terms of the radius of gyration, the hydrodynamic radius and the intrinsic viscosity. In the thermodynamically stable region, the coil size obeyed the scaling theory. However, a kinetic study of the collapse has demonstrated a two-stage collapse process in agreement with the theoretical prediction of Grosberg et al. Experimental results of the coil-to-globule transition from polystyrene in cyclohexane and from a polyelectrolyte (sodium polystyrene solfonate) in aqueous solution are presented.