1. BASF AG, Polymer Research, Department of Polymer Physics, 67056 Ludwigshafen, Germany
2. Max-Planck-Institut für Polymerforschung, Postfach 3148, D-55021 Mainz, Germany
3. Institut für Makromolekulare Chemie, Universität Freiburg, Stefan-Meier Str. 31, D-79104 Freiburg
4. Department of Chemistry, McMaster University, 1280 Main St. W., Hamilton, ON, L8S 4M1 Canada