1. Institute of Polymer Materials, Faculty of Materials Science and Applied Chemistry, Riga Technical University, P. Valdena 3/7, Riga LV-1048, Latvia
2. Faculty of Materials Science and Applied Chemistry, Institute of Materials and Surface Engineering, P. Valdena 3/7, Riga LV-1048, Latvia
3. Department of Materials Research and Technology (MRT), Luxembourg Institute of Science and Technology (LIST), 5 Avenue des Hauts-Fourneaux, L-4362 Esch-sur-Alzette, Luxembourg