Achieving extreme pressure resistance to liquids on a super-omniphobic surface with armored reentrants

Abstract

Static repellency and pressure resistance to liquids are essential for high-performance super-omniphobic surfaces. However, these two merits appear mutually exclusive in conventional designs because of their conflicting structural demands: Static liquid repellency necessitates minimal solid–liquid contact, which in turn inevitably undercuts the surface's ability to resist liquid invasion exerted by the elevated pressure. Here, inspired by the Springtail, these two merits can be simultaneously realized by structuring surfaces at two size scales, with a micrometric reentrant structure providing static liquid repellency and a nanometric reentrant structure providing pressure resistance, which dexterously avoids the dilemma of their structural conflicts. The nanometric reentrants are densely packed on the micrometric ones, serving as “armor” that prevents liquids invasion by generating multilevel energy barriers, thus naming the surface as the armored reentrants (AR) surface. The AR surface could repel liquids with very low surface tensions, such as silicone oil (21 mN m−1), and simultaneously resist great pressure from the liquids, exemplified by enduring the impact of low-surface-tension liquids under a high weber number (>400), the highest-pressure resistance ever reported. With its scalable fabrication and enhanced performance, our design could extend the application scope of liquid-repellent surfaces toward ultimate industrial settings.