INVESTIGADORES
CORREA Nestor Mariano
artículos
Título:
PRODAN Dual Emission Feature to Monitor BHDC Interfacial Properties Changes with the External Organic Solvent Composition
Autor/es:
FEDERICO AGAZZI; JAVIER RODRIGUEZ; R DARIO FALCONE; JUANA J SILBER; N MARIANO CORREA *
Revista:
LANGMUIR
Editorial:
AMER CHEMICAL SOC
Referencias:
Lugar: Washington; Año: 2013 p. 3556 - 3566
ISSN:
0743-7463
Resumen:
We have investigated the water/benzyl-n-hexadecyldimethylammonium
chloride (BHDC)/n-heptane:benzene
reverse micelles (RMs) interfaces properties using 6-propionyl-
2-(N,N-dimethyl)aminonaphthalene, PRODAN, as molecular
probe. We have used absorption and emission (steady-state and
time-resolved) spectroscopy of PRODAN to monitor the changes
in the RMs interface functionalities upon changing the external
organic solvent blend. We demonstrate that PRODAN is a useful
probe to investigate how the external solvent composition affects
the micelle interface properties. Our results show that changes in
the organic solvent composition in water/BHDC/n-heptane:benzene RMs have a dramatic effect on the photophysics of
PRODAN. Thus, increasing the aliphatic solvent content over the aromatic one produces PRODAN partition and PRODAN
intramolecular electron transfer (ICT) processes. Additionally, the water presence in these RMs makes the PRODAN ICT
process favored with the consequent decreases in the LE emission intensity and a better definition of the charge transfer (CT)
band. All this evidence suggests that the benzene molecules are expelled out of the interface, and the water−BHDC interactions
are stronger with more presence of water molecules in the polar part of the interface. Thus, we demonstrate that a simple change
in the composition of the external phase promotes remarkable changes in the RMs interface. Finally, the results obtained with
PRODAN together with those reported in a previous work in our lab reveal that the external phase is important when trying to
control the properties of RMs interface. It should be noted that the external phase itself, besides the surfactant and the polar
solvent sequestrated, is a very important control variable that can play a key role if we consider smart application of these RMs
systems.