Surface modification of chitosan membranes by alkane vapor plasma

Alkane (petroleum ether) vapor plasma technique was used for surface modification of chitosan membranes to control their permeation rate of water-soluble drugs and metabolites. Water contact angles of the chitosan surface increase from 13° to 23° after plasma treatment at 93 W for 60 min, and from 13° to 26° after plasma treatment at 119 W for 30 min, indicating reduced hydrophilicity of the membrane surface. Mechanical properties such as tensile strength and elongation-at-break of the chitosan membranes were also improved. In particular, there was a 6–7 fold increase in tensile strength in the wet state for the chitosan membrane treated at 93 W for 30 min. Permeation coefficients through the chitosan membrane plasma treated at 93 W for 30 min for urea, creatinine, uric acid, and cis-DDP decreased by 54.0%, 83.3%, 64.7% and 47.6%, respectively.