Spontaneous Emulsification of Alkanes Monitored by Multiple Light Scattering

When propylene oxide/ethylene oxide (PO/EO) surfactants were initially placed in the oil phase, long-chain alkanes with poor water solubility were emulsified spontaneously upon contact with the aqueous phase. This formation of oil droplets under static conditions was monitored and the efficiency of spontaneous emulsification was quantified using multiple light scattering (MLS). The effect of the initial surfactant phase on the interfacial tension and moduli was investigated using an interfacial tensiometer. The utilization efficiency of the surfactant and energy under external energy inputs was compared by analyzing the droplet size of the emulsions using microscopic observation and dynamic light scattering. The surfactant with the highest efficiency of spontaneous emulsification could disperse crude oil, which was used to address crude oil spill incidents in cold marine environments. To the best of our knowledge, this is the first study to monitor spontaneous emulsification under static conditions using MLS. This spontaneous emulsification under static conditions depended on the spontaneous diffusion of the PO/EO surfactants from the oil phase into the aqueous phase and on their interactions with the oil molecules. The findings of this study provide insights into the application of MLS to monitoring spontaneous emulsification.