1. Faculty of Physics, Vilnius University, Sauletekio Av. 3, LT-10257 Vilnius, Lithuania
2. Department of Structural Analysis of Materials, Center for Physical Science and Technology, Sauletekio Av. 3, LT-10257 Vilnius, Lithuania
3. Institute of Polymer Materials, Faculty of Materials Science and Applied Chemistry, Riga Technical University, P. Valdena 3/7, LV-1048 Riga, Latvia