Directional self-motion of nanodroplets driven by controlled surface wetting gradients

The self-propelled movement of droplets is essential for numerous applications. To obtain a microscopic insight on the self-propelling dynamics of droplets, droplet movement under different surface wettability gradients needs to be studied. In this study, a method is proposed to control the droplet motion using a continuous surface wettability gradient via molecular dynamics simulation. The effects of single gradient, continuous gradient, and nonlinear complex wetting gradient on the self-propelling dynamics of droplets are investigated. The results show that the droplet motion can be driven in a directional way by carefully designing the wetting gradient surface. On a single wetting gradient surface, the droplet speed increases with the wettability gradient. On a linear continuous wetting gradient surface, the droplet trajectory is consistent with the gradient direction. On a complex wetting gradient surface, the droplet trajectory can be a circle, a sine function curve, or a U-shaped curve. By ingeniously designing the wetting gradient surface, the proposed method for the self-propelled movement of droplets can be extended to more interesting paths. This study presents a microscopic perspective on the directional self-propelled movement of droplets on surfaces with wettability gradient and provides guidance for the application of droplet directional transport.

Automated summary

In this study, a method is proposed to control the self-propelling dynamics of droplets using a continuous wettability gradient via molecular dynamics simulation. The effects of single gradient, continuous gradient, and nonlinear complex wetting gradient on droplet motion are investigated. The results show that the droplet motion can be driven in a directional way by designing the wetting gradient surface.