Elastocapillary Adhesion with Soft Gels with Professor Katharine E. Jensen from Department of Physics, Williams College

Please join us to hear from Professor Katharine E. Jensen from Department of Physics, Williams College on the following:

Establishing an adhesive contact between two materials requires two things: that surface energies favor the creation of an interface, and that it be possible to form a contact area given the material geometry and properties. While elasticity has long been understood to be important in determining the relative “stickiness” between non-conformal surfaces, in recent years capillary forces have emerged as playing key roles in adhesion with highly compliant materials. For example, recent studies have demonstrated that solid surface tension can compete with or dominate over bulk elasticity in governing contact mechanics on small length scales, and mounting evidence suggests that the internal free fluid phase of compliant polymer gels also contributes significantly to mechanical response via both poroelasticity and classic capillary wetting. In this work, we experimentally investigate the adhesion between polydimethylsiloxane (PDMS) gels and rigid glass substrates. We report experiments that combine sensitive, high-speed force measurements with 2D and 3D optical imaging. By varying the asperity size, adhesion energy, and gel material properties, we gain insight into the fundamental physical processes that dominate soft contact with rough surfaces across length and time scales.