Bio-inspired micro- and nanostructures are emerging as novel dry adhesives owing to their high aspect ratio micropillar structure, resulting in collective van der Waals attraction between the adhesive and the substrate. Specifically, gecko-inspired structures exhibit great adhesive properties on smooth surfaces; however, the pull-off strength of micropillars in gecko-inspired surfaces can be decreased by applying a preloading force. Therefore, octopus suckers or suction cup-like structures have been considered as alternative microstructures providing high adhesion force. The fabrication of both microsuckers and micropillar structures is complicated and requires sophisticated control of the microstructure using photolithography and sequential polymer-based replica molding. Therefore, in this study, a fabrication method for octopus-like and suction cup-like micropatterns on polymer matrix is suggested by simple replica molding using a single master wafer. The relationship between the total adhesion force and the effective surface area of micropatterns was established and calculated by summing the preloading force, the suction force in the normal direction, and the shear force induced by van der Waals attraction. The results of adhesion force measurement and the repeatability test show that the micropatches with square microholes have high adhesion force (16N/cm2) and good repeatability of attachments/detachments over 100 cycles.

Polydimethylsiloxane Suction Cup Dry Adhesive Shear Stress

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