Nanoscale particle-droplet coalescence-induced jumping on superhydrophobic surfaces: Insights from molecular dynamics simulations

C Xue and X Han and JN Liu and A Hubao and ZB Yang and HL Wang, COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS, 703, 135171 (2024).

DOI: 10.1016/j.colsurfa.2024.135171

The removal of solid particles from superhydrophobic surfaces via coalescence-induced droplet jumping has gained increasing attention. However, the underlying mechanisms, especially the nanoscale dynamics of particledroplet coalescence, remain largely underexplored. In our research, we employ molecular dynamics simulations to investigate the influences of the radius, wettability, and arrangement of solid particles on the particle-droplet jumping velocity and energy conversion efficiency. We observe notable rotational motions during the jumping events. Our findings reveal that the arc length of the wetted area on spherical particles and the spreading time of droplets exhibit a power- law relationship. As the particle-to-droplet radius ratio increases, the jumping velocity and energy conversion efficiency initially increase but subsequently decrease. Moreover, enhanced particle wettability leads to an increase in jumping velocity while a slight decrease in translational energy conversion efficiency. The velocities of coalescence-induced particle-droplet jumping at the nanoscale are consistent with predictions from the momentum model. Significantly, our results show that the rotationally symmetric multiparticle arrangements can effectively enhance the jumping velocity and energy conversion efficiency, thus improving particle removal efficiency. Our study not only deepens the understanding of coalescence-induced particle-droplet jumping behaviors, but also provides a foundation for developing more effective particle removal strategies on superhydrophobic surfaces.

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