Advanced Materials: TechConnect Briefs 2015Advanced Materials TechConnect Briefs 2015

Advanced Materials for Engineering Applications Chapter 7

Directional liquid gating by hydrophilic/hydrophobic Janus membranes

X. Tian
Aalto University, Finland

pp. 465 - 468

Keywords: wettablity, hydrophilic/hydrophobic, Janus membranes, directional liquid transport, fluid diode

The ability to gate (i.e., allow or block) droplet and fluid transport in a directional manner represents an important form of liquid manipulation and has tremendous application potential in fields involving intelligent liquid management. We have shown theoretically that a hydrophilic/hydrophobic Janus membrane with a transmembrane chemical gradient can induce directional liquid gating due to its anisotropic liquid critical breakthrough pressure.1) Here we experimentally prepare hydrophilic/hydrophobic Janus membranes by facile vapor diffusion or plasma treatments.2) The resultant Janus membrane evidences directional water droplet gating behavior in air-water systems. Moreover, membrane-based directional gating of continuous water flow is demonstrated, enabling Janus membranes to act as facile fluid diodes for one-way flow regulation. Additionally, in oil-water systems, the Janus membranes show directional gating of droplets with integrated selectivity for either oil or water. The remarkable gating properties of the Janus membranes open new perspectives for fluid rectifying, microchemical reaction manipulation, advanced separation, biomedical materials and smart textiles.