Rob Style (ETH, Zurich) - Surface stresses in soft solids: measurements and implications

Like liquids, solids can have a surface tension, and recent work has shown how this can play a dominant role in the mechanics of very soft solids (particularly at small length scales). However, unlike in liquids, surface tension in solids should be strain dependent, and a tensor quantity. I’ll show how we measure this strain dependence, we believe for the first time, finding that the surface tension is very strongly dependent upon strain. Then I’ll talk about a few interesting implications of this observation of a strong surface elasticity, including its effect on experimental measurements in soft gels, and on fundamental solutions in linear elasticity.