The relaxation dynamics of single flow-stretched polymers in semidilute to concentrated solutions

Recent experiments on the return to equilibrium of solutions entangled polymers stretched by extensional flows [Zhou and Schroeder, Phys. Rev. Lett. 120, 267801 (2018)] have highlighted possible role tube model’s two-step mechanism in process chain relaxation. In this paper, motivated these findings, we use a generalized Langevin equation (GLE) study time evolution, under linear mixed flow, dimensions single finitely extensible Rouse polymer solution other polymers. Approximating memory function GLE, which contains details interactions with its surroundings, power law defined two parameters, show that decay chain’s fractional extension steady state can be expressed terms combination Mittag-Leffler functions. For special cases elongational flow shear after adjustment parameters function, our calculated curves provide satisfactory fits experimental from work Zhou Schroeder earlier Teixeira et al. [Macromolecules 40, 2461 (2007)]. The non-exponential character functions consequent absence characteristic constants suggest melt relaxation may proceed sequence steps an essentially continuous, rather than discrete, spectrum timescales.