Nanoparticle-free and self-healing amphiphobic membrane for anti-surfactant-wetting membrane distillation

In membrane distillation (MD), complicated feed water with amphiphilic contaminants induces fouling/wetting of the MD membrane and can even lead to process failure. This study reports a facile approach to fabricate robust and self-healing hybrid amphiphobic membranes for anti-surfactant-wetting MD based on the ultra-low surface energy of fluorinated polyhedral oligomeric silsesquioxanes (F-POSS) and its thermal induced motivation and rotation. The thermal treatment makes the membranes achieving amphiphobicity at a very low cost of F-POSS (13.04 wt.%), which is about 1/3 of without thermal treatment. The prepared membrane exhibits excellent amphiphobicity, i.e. ethanol contact angle of 120.3°, without using environmentally toxic fluorinated nanoparticles. Robust MD performance was observed for the amphiphobic membrane in concentrated sodium dodecyl sulfate (SDS) feed solutions. Furthermore, the fabricated membrane exhibited stable amphiphobicity even in extreme environments, including strong acid or alkaline solutions. In the event of a damaged or abraded membrane surface where the F-POSS can be removed, the amphiphobic membrane exhibits self-healing ability with additional thermal treatment. This simple approach without the use of nanoparticles provides an environmentally friendly way for fabrication of amphiphobic membranes for anti-surfactant-wetting membrane distillation.