Discretely Supported Dry Adhesive Film Inspired by Biological Bending Behavior for Enhanced Performance on a Rough Surface

Biologically inspired dry adhesion has recently become a research hot topic because of its practical significance in scientific research and instrumental technology. Yet, most of the current studies merely focus on borrowing the concept from some finer biological contact elements but lose sight of the foundation ones that play an equally important role in the adhesion functionality. Inspired by the bending behavior of the flexible foundation element of a gecko (lamellar skin) in attachment motion, in this study, a new type of dry adhesive structure was proposed, wherein a mushroom-shaped micropillar array behaving as a strongly adhesive layer was engineered on a discretely supported thin film. We experimentally observed and analytically modeled the structural deformation and found that the energy penalty could be largely reduced because of the partial shift from pillar bending to film bending. Such behavior is very analogous in functionality to the lamellar skin in a gecko's pads and is helpful in effectively limiting the damage of the contact interface, thus generating enhanced adhesion even on a rough surface.