Domino Patterning of Water and Oil Induced by Emulsion Breaking

Patterning of water or oil is of great significance in microfluidics and printing; however, it is still a great challenge to achieve the synchronous patterning of water and oil. Here, we report a distinct Domino patterning of water and oil, simultaneously originating from O/W emulsions. The O/W emulsions first form various emulsion patterns on the textured substrates due to local capillary differences. With the evaporation, the emulsion breaking in emulsion patterns propagates from the boundary toward the center along the radial direction, followed by the formation of water droplet arrays like a Domino. Combining patterned substrates with the Domino patterning, a variety of polymer patterns, including circle-dot arrays, quadrangle-dot arrays, and triangle-dot arrays on tens of micrometers, are successfully produced on the substrates. The Domino patterning may provide a new view for phase separation patterning, liquid directional transport, and block polymer patterns.