1. The Key Laboratory of Functional Polymer Materials and Institute of Polymer Chemistry, College of Chemistry, Nankai University, Tianjin 300071, China
2. Max-Planck-Institute for Polymer Research, Ackermannweg 10, Postfach 3148, D-55128, Mainz, Germany
3. Chemistry Department, Stony Brook University, Stony Brook, New York 11794-3400