Adhesion of Biologically Inspired Oil-Coated Polymer Micropillars

摘要

This paper presents the performance of a beetle foot-hair inspired polymer microfibrillar wet adhesive.Micropatterned poly(dimethylsiloxane)arrays of low aspect ratio cylinders are fabricated using optical lithography and molding techniques.A thin layer of viscous silicone oil is applied via stamping.The synthetic micropillar wet adhesive is characterized with a custom tensile adhesion measurement setup by varying the retraction speed,preload,contact time,oil viscosity and oil volume.An enhancement of adhesion up to 25% over the same micropattern without any applied liquid is demonstrated on a smooth substrate.A thicker silicone layer is shown to increase the adhesion of the micropillars by a factor of almost 6 on a 650 nm root-mean-square rough slightly polished aluminum surface.A model is also developed that combines surface tension and dynamic viscous forces to predict the adhesive performance.This model matched experimental data with reasonable tuning of only a single parameter.These results are used to propose further advancements in the design and fabrication of synthetic wet micropatterned adhesives.