Flexible confinement leads to multiple relaxation regimes in glassy colloidal liquids

TL;DR

This study investigates how flexible confinement influences relaxation dynamics in glassy colloidal liquids, revealing multiple regimes including unexpectedly fast relaxation at high pressures due to boundary-induced local ordering.

Contribution

It demonstrates that flexible confinement induces multiple relaxation regimes in glassy colloidal systems, highlighting the role of boundary flexibility and local ordering in relaxation behavior.

Findings

Relaxation is Arrhenius at low and moderate pressure.

At high pressure, relaxation becomes faster than expected.

Flexible walls cause local density decrease near boundaries.

Abstract

Understanding relaxation of supercooled fluids is a major challenge and confining such systems can lead to bewildering behaviour. Here we exploit an optically confined colloidal model system in which we use reduced pressure as a control parameter. The dynamics of the system are ``Arrhenius'' at low and moderate pressure, but at higher pressures relaxation is faster than expected. We associate this faster relaxation with a decrease in density adjacent to the confining boundary due to local ordering in the system enabled by the flexible wall.