1. Department of Chemistry, University of MassachusettsAmherst, 710 North Pleasant Street, Amherst, Massachusetts 01003, NOBIPOL, Department of Biotechnology, The Norwegian University of Science and Technology, NO-7491 Trondheim, Norway, Laboratoire de Physico-Chimie des Polymeres, UMR CNRS 7615, ESPCI, Université Paris 6, 75231 Paris, France, and Fraunhofer-Institut für Angewandte Polymerforschung, D-14476 Potsdam-Golm, Germany