1. Department of Physics, University of Ioannina, 451 10 Ioannina, Greece
2. Max Planck Institute for Polymer Research, Ackermannweg 10, 55128 Mainz, Germany
3. TOBB University of Economics and Technology, Söğütözü Cad. 43, 06560 Ankara, Turkey
4. Institut für Chemie, Universität Osnabrück, D-49069 Osnabrück, Germany
5. Foundation for Research and Technology, Biomedical Research Institute, Ioannina, Greece