Stability, deformation and rupture of Janus oligomer enabled self-emulsifying water-in-oil microemulsion droplet
Peer reviewed, Journal article
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Microemulsion exists widely in nature, daily life and industrial manufacturing, including petroleum production, food processing, drug delivery, new materials fabrication, sewage treatment, etc. The mechanical properties of microemulsion droplets and the correlation to their molecular structures are of vital importance to those applications. Despite researches on their physicochemical determinants, there are lots of challenges to explore mechanical properties of microemulsion by experimental studies. Herein, atomistic modelling was utilized to study the stability, deformation, and rupture of Janus oligomer enabled water-in-oil microemulsion droplets, aiming for revealing their intrinsic relationship to the Janus oligomer based surfactants and oil structures. The self-emulsifying process from a water, oil and surfactant mixture to a single microemulsion droplet was modulated by the amphiphilicity and the structure of the surfactants. Four microemulsion systems with interfacial thickness in the range of 7.4-17.3Å were self-assembled to explore the effect of the surfactant on the droplet morphology. By applying counter forces on the water core and the surfactant shell, the mechanical stability of microemulsion droplets was probed at different ambient temperatures. A strengthening response and a softening regime before and after a temperature-dependent peak force were identified followed by final rupture. This work demonstrates a practical strategy to precisely tune mechanical properties of a single microemulsion droplet, which can be applied in the formation, demulsification, and design of microemulsion in oil recovery and production, drug delivery and many other applications.