1. College of Polymer Science and Engineering, State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu, Sichuan 610065, P. R. China
2. Department of Polymer Engineering, University of Akron, Akron, Ohio 44325, United States
3. Institute of Polymer Science and Engineering, Hebei University of Technology, Tianjin 300130, China
4. Department of Macromolecular Science and Engineering, Case Western Reserve University, Cleveland, Ohio 44106-7202, United States