Reptation and constraint release dynamics in bidisperse polymer melts.

摘要: Bidisperse melts of linear, entangled polymer chains were studied using dissipative particle dynamics. The entanglement constraints mimicked with our newly developed slip-spring approach. compositions cover blends short matrix chains, slightly above the molecular weight as well both chain lengths exhibit distinct dynamics at various fractions. Struglinsky-Graessley parameter Gr, which is ratio between relaxation time long due to pure reptation and tube caused by constraint release, ranges values high below unity. We compare model simulations that use conventional generic models where bond crossings are prevented excluded-volume interactions find fairly good agreement in terms mean squared displacement. However, approach requires only a fraction computational time, making large scale systems feasible. dynamical interference two different discussed release For bidisperse melt Gr 1.0), we strong evidence reptate inside dilated whose diameter increases an exponent 1/2 towards lower chains. Furthermore observe linear relation fraction. Therefore, based on times, results support validity dilation proposed Doi et al. [Macromolecules 20, 1900–1906 (1987)].