Geometry-induced friction at a soft interface

Fuente: arXiv
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Main Authors: Chawla, Aashna, Kumar, Deepak
Format: Preprint
Published: 2024
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author Chawla, Aashna
Kumar, Deepak
author_facet Chawla, Aashna
Kumar, Deepak
contents Soft and biological matter come in a variety of shapes and geometries. When soft surfaces that do not fit into each other due to a mismatch in Gaussian curvatures form an interface, beautiful geometry-induced patterns emerge. In this paper, we study the effect of geometry on the dynamical response of soft surfaces moving relative to each other. Using a novel experimental scheme, we measure friction between a highly bendable thin polymer sheet and a hydrogel substrate. At this soft and low-friction interface, we find a strong dependence of friction on the relative geometry of the two surfaces - a flat sheet experiences significantly larger friction on a spherical substrate than on planar or cylindrical substrate. We show that the stress developed in the sheet due to its geometrically incompatible confinement is responsible for the enhanced friction. This mechanism also leads to a transition in the nature of friction as the sheet radius is increased beyond a critical value. Our finding reveals a hitherto unnoticed non-specific mechanism of purely geometrical origin that may influence friction significantly in soft, biological, and nano-scale systems. In particular, it provokes us to re-examine our understanding of phenomena such as the curvature dependence of biological cell mobility.
format Preprint
id arxiv_https___arxiv_org_abs_2404_03255
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Geometry-induced friction at a soft interface
Chawla, Aashna
Kumar, Deepak
Soft Condensed Matter
Soft and biological matter come in a variety of shapes and geometries. When soft surfaces that do not fit into each other due to a mismatch in Gaussian curvatures form an interface, beautiful geometry-induced patterns emerge. In this paper, we study the effect of geometry on the dynamical response of soft surfaces moving relative to each other. Using a novel experimental scheme, we measure friction between a highly bendable thin polymer sheet and a hydrogel substrate. At this soft and low-friction interface, we find a strong dependence of friction on the relative geometry of the two surfaces - a flat sheet experiences significantly larger friction on a spherical substrate than on planar or cylindrical substrate. We show that the stress developed in the sheet due to its geometrically incompatible confinement is responsible for the enhanced friction. This mechanism also leads to a transition in the nature of friction as the sheet radius is increased beyond a critical value. Our finding reveals a hitherto unnoticed non-specific mechanism of purely geometrical origin that may influence friction significantly in soft, biological, and nano-scale systems. In particular, it provokes us to re-examine our understanding of phenomena such as the curvature dependence of biological cell mobility.
title Geometry-induced friction at a soft interface
topic Soft Condensed Matter
url https://arxiv.org/abs/2404.03255