Microtemplated Electrowetting for Fabrication of Shape-Controllable Microdomes in Extruded Microsucker Arrays toward Octopus-Inspired Dry/Wet Adhesion

Inspired by the prominent adhesion ability of octopus suckers, many dry/wet adhesives with specific micro-structure have been fabricated for applications in smart robots, manipulators, and medical treatments. However, the reported octopus-inspired adhesive patches are either suction-assistant without tight-sealing, or suction-sealed but inefficient under both dry/wet environments. Here, a microtemplated electrowetting method is developed for the fabrication of reversible dry/wet adhesive pads consisting of extruded microsuckers with suction-enhanced microdomes and sealing-ring tips. The mechanism toward the morphology regulation of microdomes illustrates the uneven electrohydrodynamic force on the liquid–air interface that changes the liquid meniscus and achieves the precise regulation of the microdomes curvature ratio (from 0.45 to 0.74). The tip spacing can be controlled (from 0 to 50 µm) by using different templates. Theoretical and experimental insights into the mechanism of the microdomes morphology and the tip spacing on adhesion are discussed. With optimized microdomes and maximized sealing-tips, this adhesive patch generates strong and repeatable adhesion on a silicon wafer in both air (≈ 86 kPa) and underwater (≈ 61 kPa) environments. Besides, considerable adhesion to the rough surfaces are also revealed. Its adhesion ability is demonstrated with stable transportation of various objects under air/underwater environments, providing a potential application in cross-media operation.