Coating zwitterionic amino acid l-DOPA to increase fouling resistance of forward osmosis membrane

► The forward osmosis membrane surface was coated zwitterionic l-DOPA. ► The hydrophilicity and charge of the membrane porous layer have been changed. ► The modified membranes in PRO mode showed less organic fouling in FO experiments. ► The direct and easy coating of l-DOPA has the potential for industrial scale up.