Scaling Behavior of Anisotropy Relaxation in Deformed Polymers

CN Lam and WS Xu and WR Chen and Z Wang and CB Stanley and JMY Carrillo and D Uhrig and WY Wang and KL Hong and Y Liu and L Porcar and C Do and GS Smith and BG Sumpter and YY Wang, PHYSICAL REVIEW LETTERS, 121, 117801 (2018).

DOI: 10.1103/PhysRevLett.121.117801

Drawing an analogy to the paradigm of quasielastic neutron scattering, we present a general approach for quantitatively investigating the spatiotemporal dependence of structural anisotropy relaxation in deformed polymers by using small-angle neutron scattering. Experiments and nonequilibrium molecular dynamics simulations on polymer melts over a wide range of molecular weights reveal that their conformational relaxation at relatively high momentum transfer Q and short time can be described by a simple scaling law, with the relaxation rate proportional to Q. This peculiar scaling behavior, which cannot be derived from the classical Rouse and tube models, is indicative of a surprisingly weak direct influence of entanglement on the microscopic mechanism of single- chain anisotropy relaxation.

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