Biologically inspired polymer microfibers with spatulate tips as repeatable fibrillar adhesives

Being inspired by gecko foot hairs, microfibers with flat spatulate tips are proposed as repeatable adhesives. They are fabricated by molding a master template fabricated using deep reactive ion etching and the notching effect. Fabricated polyurethane fiber arrays with 4.5μm fiber and 9μm tip diameter demonstrated macroscale adhesion pressures up to 18N∕cm2 and overall work of adhesion up to 11J∕m2 on a 6mm diameter glass hemisphere for a preload pressure of 12N∕cm2. These results show around four times higher adhesion and five times higher overall work of adhesion as compared to the flat polyurethane surface.