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