JÁNÉ Eduard International Laser Centre, Comenius University in Bratislava

Ultrafast Dynamics of Nanostructured Confined Systems based on Coumarin/Cyclodextrine/Micelle

Co-authors SZÖCS Vojtech, PÁLSZEGI Tibor, GRANČIČOVÁ Oľga, ŽITŇAN Michal, BUGÁR Ignác, LORENC Dušan, HLAVÁČ Stanislav, VELIČ Dušan

The main motivation is to study confined water dynamics. There are two major approaches, the first one is to study fluorescence of probe and the second one is to study direct vibration relaxation of water. The fluorescence probe, coumarin C522, is confined in reverse micelle. The water core in reverse micelles is variable, so the environment (water structure) of the C522 is modified. The fluorescence maxima of supramolecular system are at 430 and 520 nm representing the interaction of C522 with heptane and from water, respectively. The bulk water fluorescence maximum is at 535 nm. Doubly confined system both with cyclodextrin and reverse micelle spectra are blue shifted. The differences in peak maxima are approximately 10 nm, 5 nm at small micelle, large micelle, respectively. The fluorescence dynamics decay times are from 6 to 14 picoseconds in both systems. The femtosecond infrared pump-probe experiment at 3300 cm-1 shows faster dynamics. This study might shed some light on water confinement.