Polypropylene (PP) membrane has been widely used in water purification and other fields owing to special pore structure, excellent mechanical properties and resistance to acids, alkalis and organic solvents. However, it is difficult for PP to introduce the hydrophilic chemical compositions for oil–water separation. Herein, superhydrophilic and underwater superoleophobic PP membranes were prepared by ALD for efficient gravity-driven oil–water separation. Owing to synergistic effect, oil contact angle of TiO₂ coated PP membrane under water can reach above 150°. Hence, TiO₂ coated PP membrane has great oil-repelling performance. Because of the superwetting property, TiO₂ coated PP membrane can easily separate oil–water mixture and have high separation efficiency (more than 95%). The outstanding recyclability and mechanical stability of TiO₂ coated PP membrane suggest the promising potential application in practical oil–water separation.

聚丙烯（PP）膜具有特殊的孔结构，出色的机械性能以及对酸，碱和有机溶剂的耐受性，因此已广泛用于水净化和其他领域。但是，PP很难引入亲水性化学成分进行油水分离。在此，通过ALD制备了超亲水性和水下超疏油性PP膜，以有效地进行重力驱动的油水分离。由于协同作用，TiO ₂包覆的PP膜在水下的油接触角可以达到150°以上。因此，涂覆有TiO _2的PP膜具有良好的拒油性能。由于超湿性，TiO ₂涂有涂层的PP膜可以轻松分离油水混合物，并且具有很高的分离效率（超过95％）。TiO ₂涂层的PP膜具有出色的可回收性和机械稳定性，表明其在实际油水分离中具有广阔的应用前景。