CS/SF was dissolved completely and then divided into two groups: one group was added with a corresponding ratio of ADA (1ADA:4CS/SF, w/w), the other was not. In the process of adding with ADA, the samples were deaerated and dried in a vacuum drying oven at 40 ◦C for about 4 h and then sprayed ADA solution on the surface of the membranes. Finally, the samples were dried thoroughly. Pure CS film was served as control. Samples were stored in a refrigerated desiccator until used.