| A study of the gas-liquid and solid-liquid surface chemistry of ionic liquids is presented, with the aim of obtaining an understanding of the molecular ordering at the interface. This fundamental investigation has possible applications in a number of industrial operations where mass transfer and energy transfer are involved, since interfaces play a very important role in those processes.;This work has made use of SFG, electrochemical impedance spectroscopy, cyclic voltammetry, and contact angle measurements in order to study the gas liquid, and solid liquid interfaces of alkylimidazolium, alkylammonium, and pyrrolidinium ionic liquids, combined with a variety of different anions. The results demonstrate that the presence of the anion and cation can he detected at the interface as well as the molecular orientation of species, for a variety of molecular geometries. Electrochemical methods provided additional means to probe the structure of the electrochemical double layer, enriching the picture of the metallic electrode interface, and acting as a complement to the spectroscopic technique.;The development of surface sensitive techniques in the last few decades has dramatically influenced the study of interfaces. The development of nonlinear optical techniques such as sum frequency generation (SFG) and second harmonic generation (SHG), has provided a deeper insight of the structure at the interface. Those techniques, along with other electrochemical and physicochemical methods, have the potential to enlarge the structural picture of the system under study. |
