1. Beijing
National Laboratory for Molecular Sciences and the Key Laboratory
of Polymer Chemistry and Physics of Ministry of Education, College
of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
2. School
of Physics and Key Laboratory of Functional Polymer Materials of Ministry
of Education, Nankai University, Tianjin 300071, China
3. Institute
of Chemistry, Chinese Academy of Sciences, Beijing 100190, China