1. Contribution from the Department of Macromolecular Chemistry and Organic Chemistry III, University of Ulm, Albert Einstein Allee 11, 89081 Ulm, Germany, Department of Biophysics, University of Ulm, Albert Einstein Allee 11, 89081 Ulm, Germany, Department of Physics, University of Illinois at Urbana-Champaign, Urbana, Illinois, 61801, and Deutsches Wollforschungsinstitut an der RWTH Aachen und Institut für Technische und Makromolekulare Chemie der RWTH Aachen, Veltmanplatz 8, 52062 Aachen, Germany