1. School of Materials Science and Engineering; Tianjin Key Laboratory of Composite and Functional Materials; Tianjin University; Tianjin 300072 China
2. Department of Chemical Engineering and Materials Science; Wayne State University; Detroit MI 48202 USA
3. School of Materials Science and Engineering; State Key Laboratory of Hollow Fiber Membrane Materials and Processes; Tianjin Polytechnic University; Tianjin 300387 China