1. State Key Laboratory for Modification of Chemical Fibers and Polymer Materials College of Materials Science and Engineering Donghua University Shanghai 201620 P. R. China
2. Department of Chemical and Biomolecular Engineering National University of Singapore Singapore 117585 Singapore
3. Department of Electrical and Computer Engineering National University of Singapore Singapore 117583 Singapore
4. Department of Mechanical Engineering National University of Singapore Singapore 117576 Singapore
5. School of Science and Engineering Chinese University of Hong Kong Shenzhen 518172 P. R. China
6. Department of Chemical and Biomolecular Engineering University of Maryland College Park MD 20742 USA