Confined shear-induced structure discretization enables re-entrant super-repellent metals

Re-entrant structures are fundamental to achieving robust liquid repellency, especially for low-surface-tension liquids. However, existing fabrication techniques often face a trade-off among mechanical durability, substrate geometry compatibility, large-area processing, and rapid production. Metals, with their inherent robustness, offer a promising substrate, but direct and efficient machining of metallic re-entrant structures remains a significant challenge. Here, we present a one-step mechanical cutting strategy, termed confined shear-induced structure discretization (CSSD), to directly fabricate high-density re-entrant architectures on planar and curved metallic surfaces. By designing a cave-trapezoid composite tool, we achieve a controlled transition from continuous ridges to discrete re-entrant units during ultra-precision diamond turning. The resulting metallic surfaces sustain a super-repellent Cassie-Baxter state for a broad range of liquids, exhibiting a water contact angle of 161.7 ± 2.2°, indicating non-wetting behavior. Notably, this approach enables rapid, large-area manufacturing, with a material removal rate of 1.068 mm³ s^-1 over areas up to 1.5 × 10⁴ mm². The re-entrant textures retain sufficient structural features after 1000 abrasion cycles to recover superhydrophobicity. This geometry-guided strategy reveals a mechanism for the scalable fabrication of discrete microstructures and offers useful guidance for extending the approach to other machining modalities.