1. Institute of Polymer Materials, Faculty of Materials Science and Applied Chemistry, Riga Technical University, P. Valdena 3/7, LV-1048 Riga, Latvia
2. Institute for Mechanics of Materials, University of Latvia, Jelgavas 3, LV-1004 Riga, Latvia
3. Institute of Materials and Surface Engineering, Faculty of Materials Science and Applied Chemistry, P. Valdena 3/7, LV-1048 Riga, Latvia
4. 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