1. Royal Veterinary and Agricultural University, Department of Natural Sciences, Thorvaldsensvej 40, DK-1871 Frederiksberg C, Denmark, Lund University, Physical Chemistry 1, Center for Chemistry and Chemical Engineering, P.O. Box 124, SE-221 00 Lund, Sweden, Risø National Laboratory, Danish Polymer Centre, Frederiksborgvej 399, DK-4000 Roskilde, Denmark, and Department of Chemistry and iNANO Interdisciplinary Nano Science Center, University of Aarhus, Langelandsgade 140, 8000 Aarhus C, Denmark