Physicists at the University of Liège have succeeded in sculpting the surface of water by exploiting surface tension. Using 3D printing of closely spaced spines, they have combined menisci to create programmed liquid reliefs, capable of guiding particles under the action of gravity alone. This is a promising advance for microscopic transport and sorting, as well as marine pollution control. The research is published in the journal Nature Communications.

Have you ever tried tilting a liquid in a glass? It’s completely impossible. If you tilt the glass, the surface of the liquid will automatically return to the horizontal … except for a small—barely visible—curvature that forms near the edge of the glass. This curvature is called a meniscus. And this meniscus is due to capillarity, a force acting on a millimeter scale and resulting from the surface tension of the liquid.

What would happen if we could create lots of little menisci over a large surface? What if these small reliefs could add up to form slopes, valleys, or even entire landscapes … liquid? This is exactly what scientists from the GRASP laboratory at the University of Liège, in collaboration with Brown University (U.S.), have succeeded in doing.