1. School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, Georgia 30332, United States
2. A. J. Drexel Nanomaterials Institute and Department of Materials Science and Engineering, Drexel University, Philadelphia, Pennsylvania 19104, United States
3. Institute of Macromolecular Chemistry of the National Academy of Sciences of Ukraine, Kharkivske Shosse 48, Kyiv 02160, Ukraine