Wettability-induced asymmetry in interfacial particle trapping in turbulent oil–water emulsions

We investigate the role of particle wettability in interfacial trapping by oil drops in a turbulent oil–water emulsion, using interface-resolved numerical simulations that account for turbulence, interface deformation, and particle–interface interactions. Using this framework, we characterise the trapping efficiency of hydrophilic, neutrally wetting and lipophilic particles. The oil–water interface is described by a phase-field method, while particle motion is resolved through a Lagrangian approach that accounts for both interfacial adhesion and wettability effects, enabling the direct simulation of asymmetric particle capture under turbulent conditions. Our results show a pronounced asymmetry in trapping efficiency with respect to neutral wetting, with a maximum attained for lipophilic particles. This asymmetry originates from the wettability-controlled equilibrium configuration of trapped particles: lipophilic particles preferentially reside on the drop side of the oil–water interface, where turbulent stresses are significantly weaker. As a result, these particles exhibit reduced detachment rates, leading to enhanced trapping efficiency compared to neutrally wetting and hydrophilic particles. Finally, we propose a minimal first-order kinetic model, whose rate coefficients are extracted from the simulations, that accurately predicts trapping efficiency as a function of particle wettability.