1. Department of Physics, University of Durham, South Road, Durham DH1 3LE, United Kingdom, Research Institute for Solid State Physics and Optics, P.O. Box 49, Budapest-1525, Hungary, GKSS Research Centre, Max-Planck-Strasse 1, D-21502 Geesthacht, Germany, School of Engineering, University of Durham, South Road, Durham DH1 3LE, United Kingdom, Makromolekulare Chemie und Institut für Polymertechnologie, Gauss-Str. 20, Bergische Universität Wuppertal, D-42097 Wuppertal, Germany, and Departamento de Química,...