Inclination‐Enabled Generalized Microfluid Rectifiers via Anisotropic Slippery Hollow Tracks

Abstract

The power of spontaneous maneuvering of microfluids that allow gas or liquid to penetrate along a single direction, is usually endowed with the wettability gradient and the Laplace pressure difference through tailoring special solid‒gas interfacial geographies. Herein, inspired by the structures on rice leaves and the slippery surfaces of the pitcher plant, anisotropic slippery hollow tracks (ASHTs) are fabricated and thus propose a class of unique inclination‐enabled bubble “diode”, on which one‐way bubble penetration can be reversibly switched on/off. The minimum transition tilt angle is subject to the tract spacing and the infused oil amount. The underlying mechanism of bubble penetration is attributed to the competition between the variable buoyancy component and the interfacial energy gradient perpendicular to the samples. A wide spectrum of generalized microfluid maneuvering capabilities is further demonstrated, including heavy oil selective penetration, underwater CO2 gas collection, and even dry/wet environment management in smart buildings, which are challenging for conventional counterparts. This framework should facilitate the development of microfluid control with favorable retainability and wide applicability in multiple fluids.