1. Polymers Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
2. NIST Center for Neutron Research, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, United States
3. Department of Materials Science and Engineering, University of Maryland, College Park, Maryland 20740, United States
4. Department of Mechanical and Aerospace Engineering, North Carolina State University, Raleigh, North Carolina 27695, United States
5. Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, Califronia 94025, United States