Topological elastic liquid diode.

On-demand liquid transportation is fundamentally important and holds great potential in various fields, such as water collection and biological engineering. However, it remains highly challenging to in situ manipulate the direction of liquid flow on a lyophilic surface. Here, a topological elastic liquid diode (TELD) that could manipulate the flow direction is developed by combining the Araucaria leaf inspired ratchet array and the elasticity of silicon rubber. The flow pathway on the lyophilic TELD can be conveniently managed by regulating the competition forces along orthogonal directions at the liquid front, which is instantly realized by adjusting the mechanical strain in TELD (mode 1 regulation) or inserting extra forces at the liquid front (mode 2 regulation). Furthermore, TELD can serve as a logic gate, stress valve, microfluidic reactor, and fog collector. Thus, the work here establishes strategies for in situ and instant manipulation of liquid flow on a lyophilic surface.