Adhesion of Bio-inspired Micropillar Arrays

Bio-inspired micropillar arrays have found broad applications in everything from human skin adhesion to robotic gripping. However, their adhesion remains too low for many practical engineering uses. To improve upon their adhesion, their detachment dynamics are investigated both on a single contact level and on an array level with in situ observation. Adhesion experiments revealed a strong dependence on preload force and a size-scale effect where smaller samples had higher normalized adhesion. The introduction of mechanical divisions within a single sample led to a more random detachment and produced adhesion that was up to 25% greater. Experiments on single roughness features resulted in a significant drop in adhesion which is attributed to an uneven preload force distribution, leading to adhesive contributions from only a fraction of the sample. These fundamental understandings of micropillar adhesion dynamics can help enable the next generation of bio-inspired adhesives and guide micropillar array design.M.A.S