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arXiv 2404.03255cond-mat.soft
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软界面处由几何诱导的摩擦

Geometry-induced friction at a soft interface

Aashna Chawla, Deepak Kumar

AI总结:

本文通过聚合物薄片与水凝胶的摩擦实验,揭示表面高斯曲率不匹配产生的应力会增强软界面摩擦并引发临界转变。

摘要:

软物质与生物物质具有多种多样的形状和几何结构。当因高斯曲率不匹配而无法彼此贴合的软表面形成界面时,会出现优美的几何诱导图案。本文中,我们研究几何对彼此相对运动的软表面动力学响应的影响。利用一种新颖的实验方案,我们测量了高度可弯曲的聚合物薄片与水凝胶基底之间的摩擦。在这一柔软且低摩擦的界面上,我们发现摩擦强烈依赖于两个表面的相对几何——平坦薄片在球形基底上所受摩擦显著大于其在平面或圆柱形基底上的摩擦。我们表明,薄片因几何不相容约束而产生的应力是摩擦增强的原因。随着薄片半径增大并超过临界值,该机制还导致摩擦性质发生转变。我们的发现揭示了一种此前未被注意到的、纯粹源于几何的非特异性机制,它可能显著影响软物质、生物及纳米尺度系统中的摩擦。特别是,它促使我们重新审视对诸如生物细胞迁移率的曲率依赖性等现象的理解。

英文摘要:

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.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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