Shape Memory Arrays Top Coated by Adjustable Mushroom with Switchable Adhesion to Both Solid and Liquid

Abstract

AbstractSwitchable adhesion, especially that responds to both solids and liquids simultaneously, has recently attracted much attention due to its wide applications. However, it is hard to endow a surface with switchable solid/liquid adhesion and high maximum solid adhesion at the same time due to the opposing requirement of solid contact fraction. In this paper, a shape memory/elasticity dual‐structure adjustable strategy to satisfy that special demand is offered. In detail, by constructing the shape memory epoxy resin arrays with spherical polyurethane mushroom on Fe3O4 doped substrate, a smart photo/thermal responsive material with switchable solid/liquid adhesion is prepared. In the work, the structure of the shape memory resin arrays can be reversibly changed between upright and collapsed states, leading to switchable solid and liquid adhesion. Meantime, the structure of the polyurethane mushroom can be squeezed to increase the contact area with the solid and spontaneously recovered, which can effectively improve the maximum solid adhesion with no effect on liquid adhesion. Furthermore, the obtained material has good cyclicity and universality, which has been applied to selectively pick silicon wafers and water droplets. The findings of this study may provide new strategies for the development of smart adhesive materials.