3D Bioinspired Microstructures for Switchable Repellency in both Air and Liquid

In addition to superhydrophobicity/superoleophobicity, surfaces with switchable water/oil repellency have also aroused considerable attention because of their potential values in microreactors, sensors, and microfluidics. Nevertheless, almost all those as‐prepared surfaces are only applicable for liquids with higher surface tension (γ > 25.0 mN m(−1)) in air. In this work, inspired by some natural models, such as lotus leaf, springtail skin, and filefish skin, switchable repellency for liquids (γ = 12.0–72.8 mN m(−1)) in both air and liquid is realized via employing 3D deformable multiply re‐entrant microstructures. Herein, the microstructures are fabricated by a two‐photon polymerization based 3D printing technique and the reversible deformation is elaborately tuned by evaporation‐induced bending and immersion‐induced fast recovery (within 30 s). Based on 3D controlled microstructural architectures, this work offers an insightful explanation of repellency/penetration behavior at any three‐phase interface and starts some novel ideas for manipulating opposite repellency by designing/fabricating stimuli‐responsive microstructures.