Abstract: “The interface between two immiscible electrolyte solutions (ITIES), formed between an organic (oil) phase and an aqueous phase, is crucial for chemical sensing and for studying all kinds of electron transfer and ion transfer reactions. Thus, solvents are critical in electrochemical reactions at ITIES. Though numerous organic phases, including viscous ionic liquid, have been reported in the literature, the use of true oils as an organic phase has scarcely been explored. In our study, we present true oils, including avocado oil, coconut oil, and walnut oil as novel organic solvents for ITIES. We observed well-defined potential windows and sigmoidal cyclic voltammograms for ion transfer. The ion transfer rate constants were also measured at true oil-water interfaces supported at nanopipette of ∼20–60 nm in radius. Furthermore, we proposed additional insights on the effect of solvent viscosity on the ion transfer rate at the liquid/liquid interface, with the viscosity of these true oils being ∼50–70 times that of 1, 2-dichloroethane. The standard ion transfer rate constants of tetrabutylammonium that we calculated are 0.21–0.32 cm / s at these true oil-water interface. This study opens up the possibility to expand ITIES platform to explore new reactions, playing significant roles in separation science, chemical sensing, chemical synthesis, catalysis, etc.”
Acknowledgment: NSF CAREER

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