Janus membranes fabricated by polydopamine (PDA) can separate oil/water mixtures, but cause the problems of clogging microchannels and reducing permeability. In this work, a facile and easily approach of PDA controlled modification was developed to fabricate Janus membranes with asymmetric wettability, which show well separation selectivity and high permeability for various oil/water mixtures. Paraffin was first penetrated into the microchannels from the bottom surface of the PVDF membrane by adjusting the water infiltration time, and DA subsequently deposited on the opposite top surface. After removed paraffin, the microchannels in the membrane was released and PVDF/PDA Janus membrane could be obtained with one hydrophilic side and another oleophobic underwater side. The pure water permeability was much higher than that of PVDF@PDA membrane (0.5 × 10⁴ L m² h⁻¹·bar⁻¹) without paraffin pre-treatment, due to the microchannels was unclogged by PDA. The permeability of PVDF/PDA-20 was 1.23 × 10⁴ L m² h⁻¹·bar⁻¹ towards light oil/water and heavy oil/water mixtures. Moreover, the separation efficiency achieved above 99.7%. More importantly, this Janus membrane has high efficiency for both oil-in-water and water-in-oil emulsions. The membrane shows good reusability, which could be applicated in complex oil/water separation systems.

由聚多巴胺 (PDA) 制造的 Janus 膜可以分离油/水混合物，但会导致堵塞微通道和降低渗透性的问题。在这项工作中，开发了一种简单易行的 PDA 控制改性方法来制造具有不对称润湿性的 Janus 膜，该膜对各种油/水混合物显示出良好的分离选择性和高渗透性。通过调整水渗透时间，首先将石蜡从 PVDF 膜的底面渗透到微通道中，DA 随后沉积在相对的顶面。石蜡去除后，膜中的微通道被释放，PVDF/PDA Janus 膜可在水下一侧亲水，另一侧疏油。纯水渗透率远高于 PVDF@PDA 膜 (0.⁴  L m ²  h ^-1 ·bar ^-1 ) 没有石蜡预处理，因为微通道未被PDA堵塞。PVDF/PDA-20对轻油/水和重油/水混合物的渗透率为 1.23 × 10 ⁴  L m ²  h ^-1 ·bar ^{-1 。}而且，分离效率达到99.7%以上。更重要的是，这种 Janus 膜对水包油和油包水乳液都具有高效性。该膜具有良好的可重复使用性，可应用于复杂的油水分离系统。