Plasma‐induced grafting of hydroxyethyl methacrylate (HEMA) onto chitosan membranes by a swelling method

Hydroxyethyl methacrylate (HEMA) was grafted onto chitosan membranes by plasma‐graft polymerization. Effects of monomer concentration, plasma power and plasma time on the amount of grafting were investigated. The results showed that there were two processes: grafting polymerization and etching of the membrane. The surface of the grafted membrane was evaluated by FTIR. Scanning electron microscopy indicated that the surface morphology of the grafted membrane could be adjusted through plasma power. Water contact angles of the chitosan surface decreased from 78.2° to 45.4° while the amount of grafting increased from 0 to 12.2%, indicating improved hydrophilicity of the membrane surface. Permeation coefficients through the original membrane, the membrane treated at 55 W for 15 min, and the membrane treated at 55 W for 30 min for creatinine were 9.12 × 10 −7 , 10.6 × 10 −7 and 8.57 × 10 −7 cm 2 s −1 , respectively. Thermogravimetry and mechanical testing showed that there were no significant changes on the bulk property of chitosan membrane after modification.