Direct Measurement of Strain-dependent Solid Surface Stress

Abstract

Surface stress, also known as surface tension, is a fundamental material property of any interface. However, measurements of solid surface stress in traditional engineering materials, such as metals and oxides, have proven to be very challenging. Consequently, our understanding relies heavily on untested theories, especially regarding the strain dependence of this property. Here, we take advantage of the high compliance and large elastic deformability of a soft polymer gel to directly measure solid surface stress as a function of strain. As anticipated by theoretical work for metals, we find that the surface stress depends on the strain via a surface modulus. Remarkably, the surface modulus of our soft gels is many times larger than the zero-strain surface tension. This suggests that surfaces stresses can play a dominant role in solid mechanics at much larger length scales than previously anticipated.

References in corpus (11)

• Elastocapillarity: Surface Tension and the Mechanics of Soft Solids
• Universal deformation of soft substrates near a contact line and the direct measurement of solid surface stresses
• Stiffening solids with liquid inclusions
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• The Deformation of an Elastic Substrate by a Three-Phase Contact Line
• Static wetting on deformable substrates, from liquids to soft solids
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• Soft wetting and the Shuttleworth effect, at the crossroads between thermodynamics and mechanics
• Strain-dependent solid surface stress and the stiffness of soft contacts

Cited by in corpus (22)

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• Viscoelastic and poroelastic relaxations of soft solid surfaces
• Gradient-dynamics model for liquid drops on elastic substrates
• Droplets sit and slide anisotropically on soft, stretched substrates
• Strain-dependent solid surface stress and the stiffness of soft contacts
• Surface tension and the strain-dependent topography of soft solids
• Nanometer-precision non-local deformation reconstruction using nanodiamond orientation sensing
• The role of crosslinking density in surface stress and surface energy of soft solids
• Measuring surface tensions of soft solids with huge contact-angle hysteresis
• Soft wetting with (a)symmetric Shuttleworth effect
• The mechanical equilibrium of soft solids with surface elasticity
• Gradients in solid surface tension drive Marangoni-like motions in cell aggregates
• On the singular nature of the elastocapillary ridge
• Soft electrowetting
• Stick-Slip Contact Line Motion on Kelvin-Voigt Model Substrates
• Emergence and Growth Dynamics of Wetting-induced Phase Separation on Soft Solids
• Surface elasticity effect on Plateau-Rayleigh instability in soft solids
• Surface-Polyconvex Models for Soft Elastic Solids
• Unravelling the multiscale surface mechanics of soft solids