Researchers at the Massachusetts Institute of Technology have found a way to allow water droplets to form arbitrary shapes on demand in specific planes. With this shape-controlled droplet, new biomedical laboratory equipment and LED displays are expected to be developed. The related papers are published in the journal Nature Communications.

Evelyn Wang, an associate professor of mechanical engineering at MIT who is in charge of the study, and her team have been working for years to create nano-patterned surfaces that can repel or attract liquids. She said: "The new technology allows us to precisely control the shape of droplets in the contact area. Unlike ordinary round droplets, these droplets can be square, hexagonal, triangular or almost any other shape according to one's needs. ”

According to reports recently organized by the Physicist Organization Network, the shape of the droplet can be controlled by the nano-pattern of the underlying material. New technologies can create denser patterns that eliminate the gaps that would inevitably occur between previous droplets. This work may lead to new droplet-based printing technologies. This drop can be completely controlled to a very tight degree, and is expected to be used for protein or DNA detection or LED display in the future.

Evelyn Wang said that this work involves computer modeling and experimental verification, using a very simple model that can well predict the various shapes that need to be created. In terms of cost, the new method is lower than the silicon-based lithography technology currently used to make microchips. In addition, this method is also more flexible in use.

Jonathan Bric, assistant professor of biomedical engineering at Virginia Tech University, who was not involved in the project, said that this work is a good extension of Howard Stone's research on droplets at Harvard University. In 2007, Stone discovered that droplets can form a polygon on a patterned surface. The main contribution of the new study is to extend the pillar with two axes of symmetry in the polygon of the droplet, which is expected to be a universal model for any possible geometry. This model is in good agreement with the experimental results and will be very useful for single-chip applications in biochips or labs.

Although the system has so far been certified to use only fresh water, the researchers believe that the platform is, in principle, suitable for almost all liquids. In the next step, they will improve the experiment and start testing other liquids.