1. Key Laboratory of Polymer EcomaterialsChangchun Institute of Applied ChemistryChinese Academy of Sciences Changchun 130022 P. R. China
2. University of Chinese Academy of Sciences Beijing 100049 P. R. China
3. Jilin Biomedical Polymers Engineering Laboratory Changchun 130022 P. R. China
4. University of Science and Technology of China Hefei 230026 P. R. China