1. Laboratoire de Chimie des Polymères, CP 206/01, Faculté des Sciences, Université Libre de Bruxelles (ULB), Boulevard du Triomphe, 1050 Brussels, Belgium
2. Department of Physics, Department of Chemistry and Biochemistry, Concordia University, 7141 Sherbrook St. West, Montreal, Canada
3. Institute of Solid State Physics, Graz University of Technology, Petersgasse 16, 8010 Graz, Austria