Scientists create rechargeable swim microrobots using oil and water

A new study, published today in Physics of nature, has shown that it is possible to create tiny, autonomous swimming robots from three simple ingredients.

By combining drops of oil with water containing a detergent-like substance, scientists found that they could produce artificial swimmers capable of swimming independently and even harvesting energy to recharge.

Oil droplets use fluctuating temperature changes in their environment to store energy and swim. When cooled, the droplets release thin “tail-shaped” threads into the environment. The friction generated between the tails and the surrounding fluid pushes the droplet, causing them to move. While heating, the droplets then retract their tail by returning to their original state, and exploit the heat of their environment to be recharged.

Researchers show that the droplets recharge multiple times and are able to swim for periods of up to 12 minutes at a time.

Dr Stoyan Smoukov, reader of chemical engineering at Queen Mary University in London and author of the study, said: “In biology, research shows that to create even the simplest artificial cells, we need more. of 470 genes. However, through this international collaboration, we are showing that by just using a few simple and inexpensive components, we can create a new type of active ingredient that can change shape and move like a living being. “

“We hope this study will open the possibility for people to engage in cutting edge science. Since the only equipment needed is a simple light microscope, people could create these micronagers with the most basic lab setups, or even at home. With thousands of swimmers per drop of water, it’s a world in a gout situation. And when it costs 7p per teaspoon, there’s something for everyone. “

Other types of artificial swimmers exist, but their movements are either driven by chemical reactions, which create bubbles that propel swimmers through fluids, or by physical forces such as magnetic or electric fields. Instead, this new class of swimmers, which are about the size of a red blood cell, are able to spontaneously assemble and move without using external forces.

Since swimmers are not harmful to other living things, scientists hope they could be used to study fundamental interactions between living organisms such as bacteria and algae.

“In nature, we often see large numbers of organisms, such as bacteria, clustering together, but our understanding of how these organisms interact with each other is incomplete. organisms, we could develop a clearer picture of how biology micronagers communicate with each other. For example, do they communicate only due to the physical act of bumping into each other, or is there- There are other chemicals or signals released into the environment essential for their interaction. ”