Heterogeneous wettability reverse osmosis membranes enabled by self‐adaptive polymer brushes for fouling resistance

Membrane fouling remains a central constraint on the efficiency, durability, and sustainability of reverse osmosis (RO) desalination. We present a self‐adaptive membrane with heterogeneous wettability, created by photoinitiated radical polymerization to graft zwitterionic (hydrophilic) and fluorinated (oleophobic) brushes. The self‐adaptive surface undergoes environmentally triggered polymer segregation, enabling autonomous adjustment of local surface chemistry, forming hydrophilic and low‐surface‐energy domains. The hydrophilic domain facilitates water transport, achieving a superior water permeance of 3.4 L m −2 h −1 bar −1 while maintaining 99.0% NaCl rejection. Crucially, the low‐surface‐energy domain effectively inhibits interface interaction to prevent foulant accumulation and accelerate foulant detachment, which confers excellent broad‐spectrum resistance. The low‐surface‐energy domain inhibits foulant adhesion and accelerates detachment, yielding flux recovery ratios of 91.0% for oil‐in‐water emulsion and 99.4% for petrochemical wastewater, substantially outperforming commercial membranes. This dynamic self‐adaptive wettability reveals a new antifouling mechanism and provides a design framework for robust desalination membranes.