Bioinspired microstructured adhesives with facile and fast switchability for part manipulation in dry and wet conditions

Abstract

The rapid growth in the miniaturized mechanical and electronic devices industry has created the need for temporary attachment systems that can carry out pick-and-place and transfer printing tasks for fragile and tiny parts. Current systems are limited by a fundamental trade-off between adhesive strength and state-changing trigger force, which causes the need for a rapidly switchable adhesive. In this study, an elastomeric microstructure is presented combining a trapezoidal-prism-shaped (TPS) and a mushroom-shaped microstructure, which overcomes the trade-off with the help of the TPS structure. The optimal design exhibits a strong adhesive strength of 87.8 kPa and a negligible detachment strength of <0.07 kPa with a low trigger shear stress of 10.7 kPa on smooth glass surfaces. The large tip-to-stem ratio (50 to 20 mu m) enhances the suction effect, allowing the microstructure to maintain its adhesive performance even in wet conditions. Pick-and-place manipulation tasks of a single and an array of ultralight parts from micrometer to millimeter scales are performed to demonstrate the capability of handling fragile and tiny parts. Moreover, it demonstrates the ability to transfer parts across water and air interfaces. This proposed microstructure offers a facile solution for manipulating microscale fragile parts in dry and wet conditions.