Janus nanofibrous composite membrane with unidirectional water transportation for high-efficiency solar-driven interfacial evaporation

Janus nanofiber membrane boasts a distinctive porous structure coupled with symmetrical selective wettability, which can significantly enhance its pollution resistance and present vast potential in the realm of interfacial water evaporation. In this study, a unidirectional water-transporting Janus composite membrane was prepared via solution-blowing and electrospinning. The hydrophilic layer was made of PVDF nanofibers decorated with ZnO nanowires (ZnONWs), while the hydrophobic layer was constructed with PVDF nanofibers embedded in Ag nanoparticles (AgNPs). When the spinning time of the hydrophobic layer is 10-15 min, the Janus membrane achieves unidirectional water transportation. The water evaporation rate of the composite membrane in 3.5 % NaCl and 3.5 % CuSO4 solutions can be as high as 7.74 kg & sdot;m- 2 & sdot;h- 1 and 10.87 kg & sdot;m- 2 & sdot;h- 1, respectively. In addition, ZnONWs and AgNPs can effectively enhance light absorption and show significant resistance to both S. aureus and E. col. In summary, the composite film has high photothermal utilization efficiency and anti-fouling performance and is expected to be applied to interfacial water evaporation systems.