Fabrication structure design of liquid marbles

Abstract:
Liquid marbles are droplets coated by super-hydrophobic particles, which could be manipulated and transported conveniently. These provide them to be a promising template for various droplet-based applications. In this paper, we developed a fabrication device to prepare liquid marbles. Three steps are considered, firstly PTFE powders spread on a liquid marble box, then dripping liquid drop on the powder layer, and vibration them to form liquid marbles. In the first step, motor voltage and lasting vibration time are the key factors that quantitatively control the falling powders. We performed experiments systematically to select 3V as the optimum working voltage of the vibration motor. To precisely control the sizes of liquid marbles, we found that the diameter of the droplet was independence of flow rates, only determined by the size of the needle, as indicated in the force balanced theory. The last vibration step is the key step to package the liquid drop completely and effectively. It is found that the suitable working voltage is in the range of 1.5 V to 3 V. Our new approach is simple and feasible, it can facilitate highly efficient prepare liquid marbles.