title: Polarity of the interface in ionic liquid in oil microemulsions.
abstract: Ionic liquid based microemulsions were characterized by absorption solvatochromic shifts, (1)H NMR and kinetic measurements in order to investigate the properties of the ionic liquid within the restricted geometry provided by microemulsions and the interactions of the ionic liquid with the interface. Experimental results show a significant difference between the interfaces of normal water and the new ionic liquid microemulsions. Absorption solvatochromic shift experiments and kinetic studies on the aminolysis of 4-nitrophenyl laurate by n-decylamine show that the polarity at the interface of the ionic liquid in oil microemulsions (IL/O) is higher than at the interface of water in oil microemulsions (W/O) despite the fact that the polarity of [bmim][BF(4)(-)] is lower than the polarity of water. (1)H NMR experiments showed that an increase in the ionic liquid content of the microemulsion led to an increase in the interaction between [bmim][BF(4)(-)] and TX-100. The reason for the higher polarity of the microemulsions with the ionic liquid can be explained in terms of the incorporation of higher levels of the ionic liquid at the interface of the microemulsions, as compared to water in the traditional systems.
authors.affiliation: Departamento de Química Física y Centro Singular de Investigación en Química Biológica y Materiales Moleculares, Universidad de Santiago, 15782 Santiago, Spain.
authors.forename: María
authors.initials: M
authors.lastname: Andújar-Matalobos
authors.forename: Luis
authors.initials: L
authors.lastname: García-Río
authors.forename: Susana
authors.initials: S
authors.lastname: López-García
authors.forename: Pedro
authors.initials: P
authors.lastname: Rodríguez-Dafonte