1. Institute of Chemistry; Saint Petersburg State University, Universitetsky Prospect 26; Saint Petersburg 198504 Russia
2. Institute of Macromolecular Compounds, Russian Academy of Sciences, Bolshoy Prospekt 31; Saint Petersburg 199004 Russia
3. Institute of Macromolecular Chemistry, Academy of Sciences of the Czech Republic, Heyrovsky Square 2; Prague 162 06 Czech Republic