1. `Petru Poni' Institute of Macromolecular Chemistry, Aleea Gr. Ghica Voda 41A, Iasi 700487, Romania
2. Institute of Thin Film and Microsensoric Technology, Kantstr. 55, Teltow 14513, Germany
3. University of Potsdam, Institute of Physics, Am Neuen Palais 10, Potsdam 14469, Germany
4. Fraunhofer Institute for Applied Polymer Research, Geiselbergstr. 69, Golm, 14476, Germany