Studies on dynamic heterogeneity in miscible polymer blends and dynamics of flexible polymers

This paper presents our three studies: (1) dynamic heterogeneity in miscible polymer blends, (2) dielectric study on the dynamics of flexible polymer chains in melts and solutions, and (3) stress relaxation of entangled polymer systems in biaxial extension. In the study of (1), we investigated the segmental and global dynamics mainly in miscible polyisoprene (PI) / poly(vinyl ethylene) (PVE) blends. Specifically, we estimated the characteristic sizes of the segmental motion. Furthermore, in order to see the effect of the concentration fluctuation (CF) on the segmental dynamics, we compared the dielectric relaxation spectra of the segmental motion between PI/PVE blend and PI-PVE diblock copolymer based on the fact that the CF amplitude is suppressed in the diblock copolymer system. In the second study, dipole inverted type-A polymers are used to investigate the detailed chain dynamics. In the third study, we determined the damping function in biaxial extensional deformation for polystyrene melts and compared with Doi-Edwards theory.