JAGOTA, Anand; BENNISON, Stephen J.: Gecko Feet Viewed from the Perspective of Elastomeric Adhesion

We apply principles of adhesion and fracture in elastomers to the recently discovered mechanism and microstructure of Gecko feet adhesion. The discussion is based on a simple model of a fibrillar surface, abstracted from the known structure of Gecko feet. We review basic findings of elastomeric adhesion, including the source of high adhesive energy (often viscoelasticity), changes in mechanism of crack propagation (crack blunting), and what constitutes intrinsic fracture toughness (energy release between cross-links). These results are applied to a simple model for a fibrillar surface to explore the possibility of large macroscopic fracture energy in an elastic material based on weak (van der Waals) local interactions. That is, we attempt to answer the question: is it possible that the fibrillar structure of a Gecko foot results in large fracture toughness without the operation of additional bulk dissipative mechanisms? Using the same structure, we discuss its possible advantage in the process of making initial adhesive contact.