A Self-Consistent Field Study of Interfacial Dynamics in Unentangled Homopolymer Fluids in a Sheared Channel

TL;DR

This paper applies a self-consistent field theory to analyze interfacial dynamics, flow, and rheology in sheared unentangled homopolymer fluids, revealing detailed transient and steady-state behaviors.

Contribution

It introduces a simplified quasi-1D DSCF model for studying interfacial phenomena in sheared polymer fluids, extending previous formulations.

Findings

Qualitative agreement with observed phenomena

Detailed profiles of composition, density, and stress

Insights into transient and steady-state behaviors

Abstract

In a preceding paper, we have presented a general lattice formulation of the dynamic self-consistent field (DSCF) theory for inhomogeneous, unentangled homopolymer fluids. Here we apply the DSCF theory to study both transient and steady-state interfacial structure, flow and rheology in a sheared planar channel containing either a one-component melt or a phase-separated, two-component blend. We focus here on the case that the solid-liquid and the liquid-liquid interfaces are parallel to the walls of the channel, and assume that the system has translational symmetry within planes parallel to the walls. This symmetry allows us to derive a simplified, quasi-one-dimensional (quasi-1D) version of the DSCF evolution equations for free segment probabilities, momentum densities, and the ideal-chain conformation tensor. Numerical solutions of the quasi-1D DSCF equations are used to study both the transient evolution and the steady-state profiles of composition, density, velocity, chain deformation, stress, viscosity and normal stress within layers across the sheared channel. Good qualitative agreement is obtained with previously observed phenomena.