Atomistic insight into pore-throat transport of Pickering emulsions stabilized by Janus nanoparticles

YH Chang and SB Xiao and R Ma and X Li and FH Zeng and JY He, COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS, 726, 137832 (2025).

DOI: 10.1016/j.colsurfa.2025.137832

Janus nanoparticle (JNP)-stabilized Pickering emulsions have demonstrated significant potential for enhanced oil recovery (EOR) applications. However, the fundamental transport mechanisms governing their behavior in porous media remain elusive. With the help of molecular dynamics (MD) simulations, both the nanomechanical properties of Pickering emulsions and their transport dynamics through nanopore throat are systematically investigated. The emulsion demonstrates remarkable mechanical strength under compression, primarily due to the robust, structured JNP shell. Emulsions with a higher JNP surface coverage (phi) exhibit enhanced stability and reduced susceptibility to the Jamin effect during passage through hydrophilic pore throats, which is attributed to their lower interfacial tension. It's noteworthy that the smaller opening angle of the pore throat is proved to intensify the geometric confinement, aggravates the Jamin effect, and increases the likelihood of JNPs detaching and adhering to the surface. While in the transport through hydrophobic pore throat, the JNP shell serves as an effective barrier that mitigates unfavorable interactions between the oil core and residual surface oil. Such shielding effect is particularly pronounced in emulsions with high phi, enabling them to maintain structural integrity and stability throughout transport. The findings provide atomic-scale insights into the structure property-transport relationships of JNP-stabilized emulsions, offering fundamental guidance for the rational design of nanoparticle-stabilized systems for EOR and other porous media applications.

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