Enhancing Adhesion of Biologically Inspired Polymer Microfibers with a Viscous Oil Coating

Using a beetle-inspired oil coating, the adhesion performance of a polymer microfiber synthetic adhesive was improved through viscous thin film effects. A 10000 cSt silicone oil layer was applied to polyurethane microfibers 50 μm in diameter and 100 μm tall with 100-μm diameter flat mushroom-shaped tips. Testing showed that the oil layer doubled the adhesion to a 6-mm diameter smooth glass hemisphere, achieving an adhesive strength of 37 N/cm2 given a preload pressure of 6 N/cm2. This work provides a simple method of enhancing the performance of existing fibrillar adhesives.