Surface modification of PVDF membrane by sulfonated chitosan for enhanced anti-fouling property via PDA coating layer

In this work, the modified poly (vinylidene fluoride) (PVDF) membranes provided an excellent hydrophilicity and the antifouling properties were fabricated via surface modification by 2-N-propyl sulfonated chitosan (PCS). Without sophisticated and environmentally hazardous operation, PCS was synthesized through ring-opening polymerization and immobilized onto the coated PVDF membrane surface in aqueous acetic acid solution and Tris-HCl buffer dopamine solution, respectively, while polydopamine (PDA) serving as a precursor coating layer. The modified membranes showed inferior BSA adsorption resulting from the construction of hydration layer via hydrogen bond between hydrophilic groups in PCS on membrane surface and water molecules. Due to the excellent hydrophilicity (39°) and minimal irreversible fouling (8.2%) of modified membrane, the water flux recovery rate up to 90.4% was easily attached after two cycles, which is 45% increasing of the PVDF membrane without modification. Additionally, the physic structure of PVDF membranes does not cause damage during surface modification.