1. DWI-Leibniz-Institute for Interactive Materials, e.V., RWTH-Aachen University, Forckenbeckstraße 50, D-52074 Aachen, Germany
2. Technical University of Cluj-Napoca, Department of Physics and Chemistry, 25 G. Baritiu Str., RO-400027 Cluj-Napoca, Romania
3. Institute of Technical and Macromolecular Chemistry, RWTH-Aachen University, Worringerweg 2, D-52074 Aachen, Germany