Displacement Mechanism of Sequential Droplets on a Wetting Confinement

The stability and uniformity of a liquid line formed by the sequential deposition of droplets are essential to the quality of products in many industry applications. In this work, a numerical model based on the front tracking method (FTM) is developed to investigate the displacement dynamics of sequential droplets on wetting confinement. We systematically examine the impact of wetting conditions and confinement width on the spreading length, morphology, and confined angle for a droplet. In addition, an analytical model is derived to predict the droplet displacement spacing for a uniform line. The analytical results align well with the numerical results, and the sequential droplets displaced with the predicted space achieve the minimum cross-section error and exhibit enhanced uniformity. Our numerical and analytical studies of droplet displacement within wetting confinement provide fundamental insights and a predictive framework for enhancing the uniformity and stability of liquid lines in precision manufacturing processes.