1. Physical Chemistry and Polymer Science and Physical and Colloidal Chemistry, Vrije Universiteit Brussel, Pleinlaan 2, B-1050 Brussels, Belgium; Laboratory of Polymer Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands; Laboratories of Polymer Technology and Materials and Interface Chemistry, Eindhoven University of Technology, P.O. Box 513, 5600 MB Eindhoven, The Netherlands; and Dutch Polymer Institute, P.O. Box 902, 5600 AX Eindhoven, The Netherlands