1. Guangxi Colleges and Universities Key Laboratory of Natural and Biomedical Polymer Materials, College of Materials Science and Engineering, Guilin University of Technology, Guilin 541004, China
2. Department of Materials Science and Engineering, Sun Yat-Sen University, Guangzhou 510275, China
3. South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou 510006, P. R. China
4. School of Chemistry and Chemical Engineering, Lanzhou Jiaotong University, Lanzhou 730070, P. R. China