Liquid robot can transform, separate and fuse like living cells

A joint research team has successfully developed a next-generation soft robot based on liquid. The research was published in Science Advances.

Biological cells possess the ability to deform, freely divide, fuse, and capture foreign substances. Research efforts have long been dedicated to replicating these unique capabilities in artificial systems. However, traditional solid-based robots have faced limitations in effectively mimicking the flexibility and functionality of living cells.

To overcome these challenges, the joint research team successfully developed a particle-armored liquid robot, encased in unusually dense hydrophobic (water-repelling) particles.

This novel next-generation soft robot benefits from both the exceptional deformability of liquid and the structural stability of solids. As a result, it can withstand extreme compression or high-impact drops, recovering its original shape like a droplet without breaking.

Leveraging these strengths, the joint research team led by Professor Ho-Young Kim from the Seoul National University College of Engineering’s Department of Mechanical Engineering, Professor Jeong-Yun Sun from the Department of Materials Science and Engineering, and Professor Keunhwan Park from the Department of Mechanical, Smart, and Industrial Engineering at Gachon University, demonstrate various functions of the liquid robot.

Similar to the liquid robot “T-1000” from the 1991 movie “Terminator 2,” this innovative robot can pass through metal bars, capture and transport foreign substances, and merge with other liquid robots. Additionally, it can move freely across both surfaces of water and solid ground.

The research team experimentally proved that the liquid robot could continuously perform these tasks and developed a technique to control its movement at desired speeds using ultrasound.

Thus, the newly developed liquid robot is expected to be utilized in biomedical and soft robotics applications, such as targeted drug delivery and therapeutic interventions inside the human body.

Furthermore, due to its ability to pass through extremely narrow spaces, it could be deployed in large numbers inside complex machinery, between obstacles in rugged terrain, and in disaster zones to conduct exploration, cleaning, chemical-based obstacle removal, and nutrient supply operations.

Hyobin Jeon, the first author of the paper, stated, “When we first started developing the liquid robot, we initially considered encapsulating a spherical droplet with particles, just as adopted in making conventional liquid marbles. However, by shifting our perspective, we came up with the idea of coating an ice cube with particles and then melting it, which significantly enhanced the stability of our robots.”

Professor Ho-Young Kim, the corresponding author, remarked, “Building upon our current findings, we are now working on technologies that will allow the liquid robot to change shape freely using sound waves or electric fields.”

Co-corresponding author Professor Jeong-Yun Sun added, “We plan to enhance the material functionality of the liquid robot to enable broader industrial applications in the future.”