1. Laboratory of Polymer Chemistry, A.I. Virtasen aukio 1, University of Helsinki, 00014 Helsinki, Finland
2. Present address: Institute of Physical Chemistry, RWTH Aachen University, Landoltweg 2, 52056 Aachen, Germany
3. Laboratory of Physical Chemistry and Electrochemistry, Helsinki University of Technology, P.O. Box 6100, FIN-2015 HUT, Finland
4. Molecular Materials, Helsinki University of Technology, P.O. Box 5100, FIN-2015 HUT, Finland