Miniature robots with a diameter of 2mm can harness energy from their surroundings and then autonomously collect and transport chemicals.
These 2mm diameter liquid robots operate submerged in a solution, transporting chemicals back and forth. (Video: Ganhua Xie/Tom Russell/Berkeley Lab)
Robots require energy to operate, typically from batteries or a power source. Even the most advanced robots can run out of power. For years, scientists have aspired to create a robot that can operate autonomously and continuously without needing an external power source.
A team of experts from the Energy Department at the Lawrence Berkeley National Laboratory (LBNL) and the University of Massachusetts Amherst has developed a miniature submarine-like liquid robot capable of diving underwater to collect valuable chemicals and then surfacing to transport them ashore, repeating this process multiple times, SciTechDaily reported on January 3rd. The new research has been published in the journal Nature Chemistry.
This is the first liquid robot that is self-powered and can operate continuously without electricity. It has the potential to become a system for drug delivery or automated chemical synthesis.
“We have broken the barrier in designing a liquid robot system that can operate autonomously by applying chemistry to control the buoyancy of an object,” said Tom Russell, a professor of engineering and polymer science at the University of Massachusetts Amherst and a member of the research team.
This robot has the potential to become a system for drug delivery or automated chemical synthesis.
Previously, other researchers had programmed liquid robots to perform tasks, but only once. Some liquid robots could carry out tasks continuously but required electricity to maintain operation. In contrast, Russell’s research team did not need to provide power because their robot derives energy or “food” from the surrounding environment through chemical applications.
Through a series of experiments at the Materials Science Division of LBNL, Russell and Ganhua Xie, another team member, discovered that feeding the liquid robot salt made it denser than the surrounding solution. Additional experiments by two experts, Paul Ashby and Brett Helms at LBNL, revealed how the liquid robot transports chemicals back and forth.
The liquid robots resemble tiny sacks with a diameter of only 2mm. Being denser than the surrounding solution, they gather in the center and collect selected chemicals. This triggers a reaction that produces oxygen bubbles, similar to small balloons, lifting the robot to the surface. Another reaction brings the robot to the edge of the container. There, they “dock” and unload their cargo. The liquid robots move back and forth like a pendulum and can operate continuously as long as there is food available.
Depending on their composition, the liquid robots can perform various tasks simultaneously. For instance, some robots can detect different gases in the environment, while others react to specific chemicals. In the near future, Russell and Xie plan to explore how to scale up the robots for larger systems and investigate how they operate on solid surfaces.
