Orientational ordering in crumpled elastic sheets

TL;DR

This study experimentally investigates how the geometry of confinement influences orientational order in crumpled elastomeric sheets, revealing wall-induced alignment and nematic correlations at low densities.

Contribution

It demonstrates the role of confinement geometry in inducing orientational order and nematic correlations in crumpled elastic sheets, with experiments suppressing plasticity and friction effects.

Findings

Sheets align with flat or curved walls depending on aspect ratio.

Nematic correlations develop at low volume fractions.

Large density fluctuations due to stacking of parallel sheets.

Abstract

We report an experimental study of the development of orientational order in a crumpled sheet, with a particular focus on the role played by the geometry of confinement. Our experiments are performed on elastomeric sheets immersed in a fluid, so that the effects of plasticity and friction are suppressed. When the sheet is crumpled either axially or radially within a cylinder, we find that the sheet aligns with the flat or the curved wall, depending on the aspect ratio of the cylinder. Nematic correlations develop between the normals of the sheets at relatively low volume fractions and the crumpled object has large density fluctuations corresponding to the stacking of parallel sheets. The aligning effect of the wall breaks symmetry and selects the direction of ordering.