Insight into the dynamic adhesion of bio-inspired mushroom-shaped micropillars

This study investigates the combined influence of rate-dependent effects, structural dimensions, and interface defects on the adhesion performance of mushroom-shaped micropillars by a finite element method. The mushroom-shaped pillar is modeled using the Prony series model, and the adhesive interaction at the interface is described by the Lennard-Jones potential function. Results show that the rate-dependent effect changes the adhesion stress distribution and detachment mode at the interface of mushroom-shaped micropillars, resulting in the optimal cap thickness gradually evolving with the retraction speed. Moreover, the rate-dependent effect inhibits the propagation of interface defects, leading to a weakened flaw-sensitivity of the adhesion performance of mushroom-shaped pillars. These interesting findings will further guide the design of micropillars in practical applications.