Picosecond Pulse Radiolysis Observation of the Formation and Spur Kinetics of Hydrated Electrons in Sodium Dodecyl Sulfate-Water-Cyclohexane-Hexanol Quaternary Microemulsions.

Abstract

The observation of electron transfer and solvation processes in liquid-liquid multiphase systems is of great challenge, especially at the interface. In this study, the formation and spur kinetics of hydrated electrons (e_aq^-) were investigated in sodium dodecyl sulfate-water-cyclohexane-hexanol microemulsions with ω values (n_water/n_surfactant) from 18 to 48 using picosecond pulse radiolysis coupled with pulse-probe UV-vis spectroscopy. Interestingly, a relatively slow formation of e_aq^- was observed, corresponding to the electron transfer from the oil phase to water pools. The evolution curves of e_aq^- were simulated by using a simplified consecutive reaction model. It demonstrated that the electrons generated in the oil phase are solvated in the water pools of the microemulsions at a close rate. Surprisingly, the addition of NaNO₃ could accelerate electron transfer into water pools. The decays of e_aq^- in the microemulsions were significantly slower than that in pure water and accelerated with increasing water content, indicating the absence of a nanoconfinement effect.