1. Department
of Chemical and Pharmaceutical Engineering, Faculty of Chemistry and
Pharmacy, Sofia University, 1 James Bourchier Avenue, 1164 Sofia, Bulgaria
2. Active
and Intelligent Materials Laboratory, School of Engineering and Materials
Science, Queen Mary University of London, Mile End Road, London E1 4NS, U.K.
3. Active and Intelligent Materials Laboratory, Department of Materials Science & Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 OFS, U.K.