Fuel Generated by Light Enables Self-Propelled Movement... Korean Researchers Develop Autonomous Micro-Robot [Reading Science]

Joint Research by Chonnam National University and University of Michigan

Featured on the Cover of "Advanced Materials"

Operates Without Batteries

Potential for Drug Delivery and Microfluidic System Applications

A domestic research team has developed a soft micro-robot technology that generates fuel using light and moves autonomously. This approach enables self-driving operation without the need for external fuel supply or batteries, garnering attention as a next-generation micro-robot technology with potential applications in targeted drug delivery, environmental monitoring, and precision manufacturing.

On April 3, the National Research Foundation of Korea announced that the research team led by Professor Hyungwoo Kim at Chonnam National University, together with the team of Professor Abdón Peña-Francesch at the University of Michigan in the United States, have developed a "fuel storage molecule" capable of generating and releasing fuel via light through international joint research. Based on this, they demonstrated a micro-robot operation technology that moves autonomously.

Photochemical-Based Fuel Carrier Molecule Design and Light-Induced Decomposition Behavior. (a) A fuel carrier molecule was designed by combining hexafluoroisopropanol (HFIP) fuel molecules with photoreactive ortho-nitrobenzyl (ONB) derivatives, which decompose upon ultraviolet light exposure. (b) In solution, as the ultraviolet irradiation time increases, the decomposition of the fuel carrier molecules progresses, resulting in a color change. Provided by Professor Hyungwoo Kim, Chonnam National University

This research was conducted as part of the Glocal R&D Support Program by the Ministry of Science and ICT and the National Research Foundation of Korea. The results were published as a cover article in the international chemistry journal "Advanced Materials" on February 28.

Fuel Generated by Light...Self-Propulsion Through Surface Tension

Micro and soft robots are considered key next-generation technologies in fields such as in vivo drug delivery, environmental monitoring, and precision manufacturing. However, as the size shrinks to the micro scale, it becomes difficult to include conventional batteries or electrical drive systems, and there is the limitation that energy must be continuously supplied from the outside.

To address this, the researchers focused on the concept of "embodied energy," where the robot structure itself stores energy and releases it when needed. They designed photochemical-based molecules that generate chemical fuel when exposed to light, allowing energy to be stored inside the robot.

These molecules release hexafluoroisopropanol (HFIP) fuel when irradiated with ultraviolet light. The released fuel creates differences in surface tension on the liquid, inducing a Marangoni flow, which allows the robot to move autonomously within the liquid.

Photochemical Fuel Release-Based Micro Robot Propulsion and Magnetic Field Direction Control. (a) Fuel carrier molecules were coated on a PET film substrate, and micro robots were fabricated including magnetic particles. (b) The robot propels forward by releasing fuel under ultraviolet irradiation on water, and the movement direction is controlled by a magnetic field. (c) By controlling ultraviolet light and magnetic fields, the micro robot moves along complex trajectories. Provided by Professor Hyungwoo Kim, Chonnam National University

The research team succeeded in implementing these molecules in the form of polymer composite films or as surface coatings, controlling the robot's movement by switching the light on and off. Additionally, by utilizing a magnetic field to adjust the direction of movement, they demonstrated autonomous operation along various trajectories.

Professor Hyungwoo Kim stated, "This technology can be utilized not only in micro-robots but also in active materials and microfluidic systems. If expanded to near-infrared-based systems in the future, it could also contribute to the development of medical micro-robots for use inside the human body."

The academic community evaluates this achievement as significant for presenting a new micro-robot actuation strategy that reduces dependence on external fuel. If the technology evolves into light-responsive systems using green light or near-infrared, it is expected to expand into a wide range of fields, including drug delivery and next-generation soft robot platforms in medical, environmental, and engineering sectors.

This content was produced with the assistance of AI translation services.