In-situ switchable superhydrophobic shape memory microstructure patterns with reversible wettability and adhesion

Abstract

Recently, more and more attention has been focused on superhydrophobic patterned surfaces with controllable wettability and adhesion. However, almost all present works are based on designing hydrophilic patterns onto the superhydrophobic surfaces. Smart wetting control on microstructure patterned surfaces is still extremely rare since reversible regulating surface microstructure is relatively more difficult. Herein, we report such a strategy for smart surface wetting control. As a demonstration, a superhydrophobic shape memory polymer (SMP) array was prepared, patterns such as dots and lines can be easily obtained through pressing structured templates on the surface, and such patterns can be removed after a further heating process. During the whole process, lots of surface wetting properties including large/small contact angles, high/low adhesions, and isotropic/anisotropic sliding abilities can be reversibly controlled. The smart controllability comes from the excellent shape memory effect (SME) of the material, which can memorize and present diverse microstructure patterns and solid/liquid contact models. Furthermore, some applications including droplet storage, capture/release, directional transportation, and special advantages compared with traditional hydrophilic patterns such as anti-pollution property and excellent stability were also demonstrated. This work not only opens a novel way for controlling surface wetting, but also provides a new superhydrophobic platform for manipulation of microdroplet.