1. Research Laboratory of Functional Materials Technologies, Faculty of Materials Science and Applied Chemistry, Riga Technical University, Paula Valdena 3/7, Riga LV-1048, Latvia
2. Institute of Physics, University of Tartu, W. Ostwaldi Street 1, Tartu EE-50411, Estonia
3. Rudolfs Cimdins Riga Biomaterials Innovations and Development Centre of RTU, Institute of General Chemical Engineering, Faculty of Materials Science, Riga Technical University, Pulka 3, Riga LV-1007, Latvia
4. Institute of Materials, École Polytechnique Fédérale de Lausanne, Lausanne CH-1015, Switzerland
5. Institute of Chemical Physics, University of Latvia, Jelgavas street 1, Riga LV-1586, Latvia
6. Latvian Institute of Organic Synthesis, Aizkraukles street 21, Riga LV-1006, Latvia
7. Institute of Solid State Physics, University of Latvia, Kengaraga street 8, Riga LV-1063, Latvia
8. Surface Science Group, Faculty of Engineering and Natural Sciences, Tampere University, P.O.
Box 692, FI-33014 Tampere, Finland