1. Laboratory of Organic and Macromolecular Chemistry, Friedrich-Schiller-University Jena, Humboldtstr. 10, D-07743 Jena, Germany, Tel.: , Fax:,
2. Dutch Polymer Institute (DPI), P.O. Box 902, NL-5600 AX Eindhoven, The Netherlands
3. Laboratory of Macromolecular Chemistry and Nanoscience, Eindhoven University of Technology, P. O. Box 513, NL-5600 MB Eindhoven, The Netherlands