Tannic acid-based functional coating: surface engineering of membranes for oil-in-water emulsion separation

physical/chemical regulation are discussed. The roles of tannic acid in surface engineering of membranes are highlighted and classified into the following five categories: changing surface wettability, adjusting surface charge, constructing catalytic surfaces, forming hydrogel surfaces, and fabricating hybrid separation membranes/layers. Finally, the future outlook and the challenges in this field are discussed.