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

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.