A Janus Mesh with Robust Interface and Controllable Wettability for Water Transport

The rational design of material structure is of great importance to the membrane material in water manipulation and management. Among them, by designing materials and structures on both sides of Janus membranes with porous structures, membranes with opposite wettability can be prepared to show directional liquid transport effects. However, the Janus membrane has the weakness of interfacial bonding due to the difference in the material and structure of the two layers. Here, we report a method to improve the interfacial bonding force of the two layers. Janus membrane is prepared using polyvinylidene fluoride hexafluoropropylene (PVDF-HFP) and cellulose acetate (CA) through the electrospinning method and then treated with sodium hydroxide (NaOH) solution. The as-prepared Janus membrane has a hydrophilic-hydrophobicity gradient and a strong bonding interface obtained by adjusting the chemical composition and microstructure. The NaOH solution plays a dominant role in forming hydrophilic-hydrophobicity gradient and enhancing the interface bonding between the bilayer membranes. The results show that this Janus membrane can achieve the purpose of oil-water separation and one-way water transmission by absorbing oil and regulating liquid surface tension. This strategy provides new ideas and technical supports for improving the Janus membrane interfacial bonding force and expands potential applications in the future.