# Dynamical structure of entangled polymers simulated under shear flow

## TL;DR

This paper uses computer simulations to analyze how entangled polymers' microscopic structures respond dynamically to shear flow, revealing directional differences in relaxation and diffusion behaviors.

## Contribution

It introduces an extended blob model simulation to study the dynamical structure of entangled polymers under shear flow, providing new insights beyond rheological descriptions.

## Key findings

- Relaxation speeds up along the flow direction.
- Relaxation slows down along the shear gradient.
- Complex diffusion behavior in vorticity direction.

## Abstract

The non-linear response of entangled polymers to shear flow is complicated. Its current understanding is framed mainly as a rheological description in terms of the complex viscosity. However, the full picture requires an assessment of the dynamical structure of individual polymer chains which give rise to the macroscopic observables. Here we shed new light on this problem, using a computer simulation based on a blob model, extended to describe shear flow in polymer melts and semi-dilute solutions. We examine the diffusion and the intermediate scattering spectra during a steady shear flow. The relaxation dynamics are found to speed up along the flow direction, but slow down along the shear gradient direction. The third axis, vorticity, shows a slowdown at the short scale of a tube, but reaches a net speedup at the large scale of the chain radius of gyration.