1. Polymers Branch, U.S. Army Research Laboratory, Aberdeen Proving Ground, Baltimore, Maryland 21005, United States
2. Bennett Aerospace, Inc., Cary, North Carolina 27518, United States
3. Department of Physics “A. Pontremoli”, University of Milan, via Celoria 16, 20133 Milan, Italy
4. Department of Chemical Engineering and Biotechnology, University of Cambridge, CB3 0AS Cambridge, United Kingdom