1. Department of Chemical Engineering and Materials Science, Michigan State University, East Lansing, MI 48824, USA
2. College of Polymer Science and Engineering, State Key Laboratory of Polymer Materials Engineering, Sichuan University, Chengdu, Sichuan 610065, P. R. China
3. Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
4. Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, Delaware 19716, USA
5. X-ray Science Division, Argonne National Laboratory, Lemont, Illinois 60439, USA
6. Center for Nanophase Materials Sciences, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA