Relaxation Processes and Dynamical Structure in Polymer Liquids

Abstract

We review recent studies of dielectric relaxation and dynamical structure in solutions and melts of cis-polyisoprene (cis-PI) which exhibit dielectric normal mode process due to the fluctuation of end-to-end distance as well as the local segmental mode process. The influences of varying molecular weight, concentration, and solvent quality on the relaxation time for the normal mode process are discussed based on the bead-spring model and the tube model. The dielectric and mechanical relaxation spectra in bulk cis-PI are compared over a wide time scale covering both the wedge and box type spectral region. The relationship between the monomeric friction coefficient and the dielectric relaxation time for the segmental mode process is also discussed.