1. Department of Polymer
Science, The University of Akron, Akron, Ohio 44325-3909, United States
2. Department of Physics and Astronomy, McMaster University, Hamilton, Ontario, Canada L8S 4M1
3. Key Laboratory of Polymer Chemistry & Physics of Ministry of Education, Center for Soft Matter Science and Engineering, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, P. R. China