Janus Membrane for Water/Bubble Unidirectional Penetration Based on Nanosecond Laser Processing

Janus membranes featuring asymmetric wettability and water/bubble unidirectional transport capabilities have emerged as revolutionary materials in fields of sustainable water management, energy conversion, and biomedical devices and have attracted great research attention. In this study, we developed a novel Janus wettable membrane fabricated by simple nanosecond laser drilling and texturing. The membrane demonstrated a tunable penetration rate for both water droplets and underwater bubbles by varying the parameters of drilling pore size and porosity. Our analysis revealed an approximately linear correlation between the optimal penetration rate and the ratio of the two structural parameters. The detailed mechanism of unidirectional penetration and the flow rate difference was analyzed. Effective fog harvesting and water-bubble selective collection were achieved by the laser-prepared Janus membrane. The combination of laser precision and adaptive structural design paves the way for next-generation Janus membranes with a broader industrial and environmental impact.