Generally Grafting Hydrophobic Polymer Brushes in Pure Water Through SIP of Phase Transfer Delivered Monomers

Abstract Hydrophilic and hydrophobic polymer brushes hold significant potential in antifouling, energy, medical, and lubrication applications. Because of rigorous polymerization conditions and requirements of organic solvents, research on hydrophobic polymer brushes is limited. Herein, we report a simple but efficient surface‐initiated polymerization technique based on phase‐transfer‐delivered hydrophobic monomers (named PTD‐SIP) that enables generally grafting hydrophobic brushes using minimal chemicals in an oxygen‐tolerant environment with high end‐group reactivity. This method employs methyl‐β‐cyclodextrins (CD) as a transport carrier to deliver hydrophobic monomers in water, eliminating the need for organic solvents. The PTD‐SIP method enables easy alternating or simultaneous grafting of hydrophilic and hydrophobic monomers and is applicable to various substrates and monomer types. Furthermore, reversible structural color has been achieved through rewritable surface‐grafted polymer brushes, while permanent inorganic hybrid coatings provided expanded opportunities for applications in optics and tribology. These features make water‐based hydrophobic polymer brushes a powerful tool for developing high‐performance interfacial materials.