Polyphenol‐Sensitized Atomic Layer Deposition for Membrane Interface Hydrophilization

Abstract Improvements in energy–water systems will necessitate fabrication of high‐performance separation membranes. To this end, interface engineering is a powerful tool for tailoring properties, and atomic layer deposition (ALD) has recently emerged as a promising and versatile approach. However, most non‐polar polymeric membranes are not amenable to ALD processing due to the absence of nucleation sites. Here, a sensitization strategy for ALD‐coating is presented, illustrated by membrane interface hydrophilization. Facile dip‐coating with polyphenols effectively sensitizes hydrophobic polymer membranes to TiO 2 ALD coating. Tannic acid‐sensitized ALD‐coated membranes exhibit outstanding underwater crude oil repulsion and rigorous mechanical stability through bending and rinsing tests. As a result, these membranes demonstrate outstanding crude oil‐in‐water separation and reusability compared to untreated membranes or those treated with ALD without polyphenol pretreatment. A possible polyphenol‐sensitized ALD mechanism is proposed involving initial island nucleation followed by film intergrowth. This polyphenol sensitization strategy enriches the functionalization toolbox in material science, interface engineering, and environmental science.