Bioinspired Super-antiwetting Interfaces with Special Liquid−Solid Adhesion

摘要

Snuper-antiwetting interfaces, such as superhydrophobic and superamphiphobic surfaces in air and superoleophobic inter-nfaces in water, with special liquid solid adhesion have recently attracted worldwide attention. Through tuning surfacenmicrostructures and compositions to achieve certain solid/liquid contact modes, we can effectively control the liquid solidnadhesion in a super-antiwetting state. In this Account, we review our recent progress in the design and fabrication of thesenbioinspired super-antiwetting interfaces with special liquid solid adhesion.nLow-adhesion superhydrophobic surfaces are biologically inspired, typically by the lotus leaf. Wettability investigated at micro-nand nanoscale reveals that the low adhesion of the lotus surface originates from the composite contact mode, a microdroplet bridg-ning several contacts, within the hierarchical structures. Recently high-adhesion superhydrophobic surfaces have also attracted researchnattention. These surfaces are inspired by the surfaces of gecko feet and rose petals. Accordingly, we propose two biomimeticnapproaches for the fabrication of high-adhesion superhydrophobic surfaces. First, to mimic a sticky gecko’s foot, we designed struc-ntures with nanoscale pores that could trap air isolated from the atmosphere. In this case, the negative pressure induced by thenvolume change of sealed air as the droplet is pulled away from surface can produce a normal adhesive force. Second, we con-nstructed microstructures with size and topography similar to that of a rose petal. The resulting materials hold air gaps in theirnnanoscale folds, controlling the superhydrophobicity in a Wenzel state on the microscale.nFurthermore, we can tune the liquid solid adhesion on the same superhydrophobic surface by dynamically controlling thenorientations of microstructures without altering the surface composition. The superhydrophobic wings of the butterfly (Morpho aega)nshow directional adhesion: a droplet easily rolls off the surface of wings along one direction but is pinned tightly against rollingnin the opposite direction. Through coordinating the stimuli-responsive materials and appropriate surface-geometry structures, wendeveloped materials with reversible transitions between a low-adhesive rolling state and a high-adhesive pinning state for waterndroplets on the superhydrophobic surfaces, which were controlled by temperature and magnetic and electric fields.nIn addition to the experiments done in air, we also demonstrated bioinspired superoleophobic water/solid interfaces withnspecial adhesion to underwater oil droplets and platelets. In these experiments, the high content of water trapped in thenmicro- and nanostructures played a key role in reducing the adhesion of the oil droplets and platelets. These findings willnoffer innovative insights into the design of novel antibioadhesion materials.