Modification Of Polyethersulfone Membrane By SI-eATRP Method And The Study Of Its Anti-fouling Property

SI-e ATRP is a simple and controllable method for preparing polymer brushes.Thus,the hydrophilicity and anti-fouling properties of the polyethersulfone membrane were improved by SI-e ATRP method.(1)Sodium polyacrylate were grafted on PES membrane using SI-e ATRP technology,and the growth of polymer brushes were controlled by polymerization time,potential,monomer concentration,and modifier concentration.The experimental results showed that the grafting time had an obvious effect on the grafting rate,but the grafting rate had no obvious change after the polymerization of 1 hour;the suitable potential could be obtained from the CV curve,and the grafting rate would be reduced at a lower or higher potential;besides,the low concentration of monomer had a serious negative effect on the polymerization,because the membrane was not dissolved in the electrolyte,the contact probability between monomer and membrane surface was relatively low;finally,the most suitable modifier content was 2 %,the higher content of the modifier caused the collapse of the membrane pore structure,resulting in the incompleteness of the membrane.(2)SI-e ATRP method was used to graft hydrophilic PAANa,PVP,and PSSNa brushes on the surface of PES membrane.The homopolymers,block copolymers,and random copolymers were prepared on the surface of membrane by controlling the order of grafting and the types of monomers in the electrolyte.We investigated the effect of homopolymer,block copolymer,and random copolymer on the properties of modified membrane.The results of mercury pressure and section scanning showed that the modified membrane had higher porosity than PES membrane.The filtration experiment results showed that there was no obvious difference in the properties between block copolymers and random copolymers.The modified membrane by grafting random polymer onto polyethersulfone membrane(M-3r)had better resistance to protein contamination than block copolymer and homopolymer.(3)PNIPAm,P(NIPAm-co-GMA),and P(NIPAm-co-Am)were grafted on the surface of PES membrane by SI-e ATRP method.PNIPAm was the thermo-responsive polymer chains,and PGMA and PAm were the hydrophobic and hydrophilic segments,respectively,which were used to adjust the flux switch.Water flux experiments at different temperatures showed that all modified membranes had thermo-sensitive characteristics.The water flux of M-PNIPAm and M-PNIPAm-co-PGMA increasedsharply at 32 °C,the water flux of M-PNIPAm-co-PAm increased sharply at 38 °C.(4)Phospholipid modification and peptide modification on membrane surface were carried out by SI-e ATRP.Zwitterionic material 2-Methacryloyloxy ethyl phosphorylcholine(MPC)and glycidyl methacrylate(GMA)containing rich epoxy groups were grafted on PES membrane by SI-e ATRP.The amino acid polypeptide REDV was immobilized on the surface by the open ring reaction with PGMA under mild conditions.The results showed that the modified membranes could effectively inhibit non-specific protein adsorption.We further adjusted the ratio of zwitterionic MPC and peptide REDV,the results of filtration experiments showed that zwitterionic modification had a more positive effect on anti-fouling than peptides.