Surface Tension and the Mechanics of Soft Materials

Surface tension is usually neglected in solid mechanics because elasticity dominates the mechanical response of stiff materials. However, for very compliant solids, the surface tension can compete with and even dominate over the elastic response. This results in counterintuitive phenomena that sometimes directly contradict the predictions of classic elastic theory. Here, I will describe solid surface tension at work two contexts: composites and adhesive contacts. In both of these examples, we find that surface tension dominates over elasticity on length scales determined by material properties, requiring us to rethink solid mechanics for soft materials. Our findings potentially impact the design of any system that relies on compliant materials with interfaces, including soft robotics, functional soft medical implants, and commercial adhesives.