Dynamic distribution of capillary microdroplet using water condensation on hydrophobic surface

A microdroplet distribution method based on water condensation on hydrophobic surface is presented to obtain micromanipulation droplet for capillary gripping. Accordingly, the droplet condition required in micro-objects transfer (pick-and-place) is investigated. Model of liquid bridge stretching is established during microdroplet dispensing. Two configurations (plane-plane, plane-sphere) of dynamic liquid bridge is modeled using VOF (Volume of Fluid) method to analyze the acquisition process of capillary micromanipulation droplet. Simulation results demonstrate that the contact angle and drawing velocity have a significant influence on the acquisition fraction of auxiliary droplet and rupture distance. The initial liquid bridge moves toward the surface with small contact angle after the formed liquid bridge rupture. Micromanipulation probes with big drawing velocity enable manipulation droplet to split on two surfaces equally. The impact of droplet volume on the acquisition fraction of auxiliary droplet is relatively small, but is proportional to the rupture distance. Configurations (plane-plane, plane-sphere) of dynamic liquid bridge are experimental investigated to verify feasibility of the proposed method.