1. Institute for Macromolecular Chemistry and Textile Chemistry, Department of Chemistry and Food Chemistry, Faculty of Science, Technische Universität Dresden, Mommsenstrasse 4, D-01069 Dresden, Germany, and Laboratory for Surface Science and Technology, Department of Materials, Swiss Federal Institute of Technology (ETHZ), Wolfgang-Pauli-Strasse 10, ETH Hönggerberg, CH-8092 Zürich, Switzerland