Preparation Janus membrane via polytetrafluoroethylene membrane modification for enhanced performance of vacuum membrane distillation desalination

•A novel Janus membrane with multilevel hierarchical structures was prepared.•The novel Janus membrane simultaneously possesses antiwetting and high-efficiency desalination properties during VMD.•The coupled effects of super hydrophilicity brought about by PDA layer and self-healing mechanism provided by Fe3O4 nanoparticles contributed to the superior performances of novel Janus membrane.