Description of Entanglement Dynamics of Flexible Polymers: Self-Consistent Coarse-Graining in Length and Time Scales

Abstract

The current tube models for the entanglement dynamics of flexible polymers are mostly based on the molecular picture of dynamic tube dilation (DTD). The full‐DTD picture, assuming the equivalence of the relaxed portions of the chains and a simple solvent at any time t, fails for binary blends of long and short linear polyisoprene (PI) chains at intermediate t, as revealed from comparison of viscoelastic and dielectric data. In contrast, the data are well described with the partial‐DTD picture that considers the extent of DTD determined by the constraint release (CR) process and achieves consistent coarse‐graining of the length and time scales. The failure of the full‐DTD picture and success of partial‐DTD picture are noted also for star‐branched PI chains. The partial‐DTD picture would serve as a good starting point for constructing refined molecular models for entangled polymers.