Controllable Directional Liquid Transport in Open Channel

Directional liquid transport has gradually drawn worldwide attention due to its diverse potential applications in precision medicine, microfluidics, and microreactors. However, previous directional liquid control usually resorts to complex hierarchical micro-nano structures, heterogeneous wettability, or external driving fields, which inevitably limits the flexibility and applicability of liquid manipulation. Here, a novel open channel surface is presented, which exhibits an on-demand directional transport performance via a shifting mechanism of weak area on liquid precursor. The coupling effect of sidewall wettability and bottom hydrophobic barrier patterns redistributes the surface pressure from the front and rear meniscus of liquid precursor, which determine the position of weak area and transport direction. The impacts of wettability and various barrier patterns on anisotropic liquid transport ability are made clear, and the design principle of unidirectional open channels without complex microstructure is validated. Smart directional transport can also be easily built by use of various stimulus materials, such as thermal responsive polymer. This controllable directional liquid transport can introduce ways for various on-demand liquid manipulations.