Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
1660170 | Surface and Coatings Technology | 2009 | 5 Pages |
Dense chitosan membranes were prepared and studied for surface modification using argon plasma produced at low pressures from 6.67–133.3 Pa with RF frequencies at a power ranging from 6–90 W. Glutaraldehyde and sulfuric acid in methanol were used as linking reagents before the plasma treatment. When the plasma density was fixed at conditions of 6 W and 49 W at 66.7 Pa, the membrane wettability was measured as a decrease in contact angle between the water drop and the membrane surface. Water swelling properties were increased in glutaraldehyde cross-linked membrane. It was found that the ionic permeability of the membranes did not depend linearly on the plasma density used. The density at 6 W was smaller than that produced at 49 W, but it increased the Cl− to K+ permeability ratio of the membranes by 1.4–1.8 times, with the maximum increase found in glutaraldehyde cross-linked membranes. Results from AFM showed that plasma treatment caused roughness at the membrane surface, and consequently, the hydraulic permeability of the membranes was reduced. Moreover, results from ATR-FTIR showed a major increase in the absorption spectra of CO, C–H, and C–O functional groups. The results were similar for the sulfuric acid cross-linked and the control membrane. In contrast, a glutaraldehyde cross-linked membrane was not affected greatly by plasma treatment. This study indicates that surface modification by argon plasma leads to changes in filtration characteristics and ionic permeability of chitosan membranes.