1. Institute of Chemistry of New Materials; University of Osnabrück; Barbarastr. 7 49069 Osnabrück Germany
2. Materials Science and Technology of Polymers; MESA+ Institute for Nanotechnology; University of Twente; P. O. Box 217 7500 AE Enschede The Netherlands
3. Department of Neurobiology; University of Osnabrück; Barbarastr. 11 49076 Osnabrück Germany