Herein, hydrophobic PVDF membranes were facilely transformed into highly hydrophilic and underwater superoleophobic ones via one-step dip-coating in tannic acid (TA)/sodium periodate (NaIO₄)-mixed solution. The employment of NaIO₄ could not only facilitate TA oxidation and deposition, but also introduce abundant hydrophilic carboxyl groups on membrane surface. Consequently, compared with the pristine PVDF membrane, the modified membrane showed much higher hydrophilicity and underwater oleophobicity with water contact angle decreasing from 121° to 32°, oil contact angle increasing from 116° to 162° and a tilt angle of just 2°. In contrast to the two-step modification (deposition of TA followed by post-oxidation by NaIO₄), our approach endowed the membrane with dramatically improved permeability (>2400 LMH/bar) and oil rejection (>98%) when dealing with different types of oil-in-water emulsions. Additionally, the membrane displayed excellent antifouling performance with flux recovery ratios of above 95% and favorable reusability after 5-cycle filtration tests. Moreover, the membrane possessed a stable TA coating even being subjected to harsh pH solutions or sonication. This work provides a simple, robust and cost-effective strategy for membrane modification.

在此，通过在单宁酸（TA）/高碘酸钠（NaIO ₄）混合溶液中进行一步浸涂，将疏水性PVDF膜轻松转变为高度亲水性和水下超疏油性膜。NaIO _4的使用不仅可以促进TA的氧化和沉积，而且可以在膜表面引入大量的亲水性羧基。因此，与原始PVDF膜相比，改性膜表现出更高的亲水性和水下疏油性，其中水接触角从121°减小到32°，油接触角从116°增大到162°，倾斜角仅为2°。与两步修饰相反（先沉积TA，然后用NaIO ₄进行后氧化）），当处理不同类型的水包油乳液时，我们的方法使膜的渗透性（> 2400 LMH / bar）和吸油率（> 98％）大大提高。此外，该膜还具有出色的防污性能，通量回收率超过95％，并且经过5次循环过滤测试后具有良好的可重复使用性。此外，该膜即使在苛刻的pH溶液或超声处理下也具有稳定的TA涂层。这项工作为膜改性提供了一种简单，可靠且具有成本效益的策略。