1. Department of Macromolecular Science and Engineering, Case Western Reserve University, Cleveland, Ohio 44106, USA
2. National Synchrotron Light Source II, Brookhaven National Laboratory, Upton, New York 11973, USA
3. Institute of Polymer Science and Engineering, Hebei Key Laboratory of Functional Polymers, Hebei University of Technology, Tianjin 300130, P. R. China
4. School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
5. Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA
6. Department of Materials Science and Engineering, Case Western Reserve University, Cleveland, Ohio 44106, USA
7. Department of Chemical and Biomolecular Engineering, National University of Singapore, Singapore 117585, Singapore