1. Department of Physics University of Ioannina P.O. Box 1186 Ioannina 451 10 Greece
2. Department of Chemistry Johannes Gutenberg Universität Mainz 55099 Mainz Germany
3. Max Planck Institute for Polymer Research 55128 Mainz Germany
4. University Research Center of Ioannina (URCI) – Institute of Materials Science and Computing Ioannina 45110 Greece