1. Institute of Functional Nano & Soft Materials Collaborative Innovation Center of Suzhou Nano Science and Technology Soochow University Suzhou 215123 P. R. China
2. Department of Chemistry and the Materials Research Center Northwestern University 2145 Sheridan Road Evanston IL 60208 USA
3. Research Center for Engineering Technology of Polymeric Composites of Shanxi Province School of Materials Science and Engineering North University of China Taiyuan 030051 P. R. China
4. Flexterra Inc. 8025 Lamon Avenue Skokie IL 60077 USA