1. Department of Polymer Science, The University of Akron, Akron, 170 University Avenue,
Akron, Ohio 44325-3909, United States
2. NIST Center for Neutron Research, National Institute of Standard and Technology, Gaithersburg,
Maryland 20899, United States
3. Department of Materials Scence
and Engineering, University of Maryland, College Park, Maryland 20742, United States