Dual hydrophilic/hydrophobic co-doping enables simultaneous enhancement of water permeance and antifouling in polyamide RO membranes

The intensifying global water shortage highlights the need for reverse osmosis (RO) membranes combining high permeability with effective fouling resistance. Herein, we report a dual-component bulk doping strategy to fabricate high-performance polyamide (PA) RO membranes by incorporating hydrophilic tris(hydroxymethyl)aminomethane (Tris) into the aqueous phase and hydrophobic (3,3,3-trifluoropropyl) triethoxysilane (TFTS) into the organic phase during interfacial polymerization (IP). The synergistic integration of Tris and TFTS achieves a breakthrough in balancing water permeance and antifouling properties. Enhanced bidirectional monomer diffusion and controlled microporosity enable the optimized Tris-TFTS-doped PA membrane to reach 3.48 L·m −2 ·h −1 (LMH) water permeance while retaining 98.54 % NaCl rejection. TFTS reduces aqueous-organic interfacial tension, promoting larger, multilayered, vertically aligned “leaf-like” PA nanostructures with increased surface roughness. Concurrently, TFTS hydrolysis generates a low-surface-energy fluorinated siloxane (Si-O-Si) network, while Tris-derived hydroxyl groups enhance surface wettability. This unique molecular architecture confers exceptional broad-spectrum antifouling performance against cationic surfactants, anionic surfactants, proteins, humic acid, and inorganic CaSO₄ through a triple defense mechanism: electrostatic repulsion, hydration layers via hydrophilic moieties, and weakened foulant adhesion from low surface energy. This scalable, a dual-component bulk doping strategy offers a promising route for advanced RO desalination membranes.