A slow process in confined polymer melts: layer exchange dynamics at a polymer solid interface

TL;DR

This study uses Molecular Dynamics simulations to reveal that layer exchange dynamics near solid interfaces in confined polymer melts are slow, influencing the glass transition process alongside packing and intramolecular barriers.

Contribution

It provides the first detailed simulation-based insight into layer exchange dynamics at polymer-solid interfaces in confined melts.

Findings

Layer exchange near walls is slow in polymer melts.

This process affects the glass transition in confined polymers.

Competes with other relaxation mechanisms like packing effects.

Abstract

Employing Molecular Dynamics simulations of a chemically realistic model of 1,4-polybutadiene between graphite walls we show that the mass exchange between layers close to the walls is a slow process already in the melt state. For the glass transition of confined polymers this process competes with the slowing down due to packing effects and intramolecular rotation barriers.