Jeonbuk National University (JBNU) Professor Kim Yong-min's research team (College of Engineering, Division of Chemical Engineering), in collaboration with Professor Moon Hong-cheol's team at KAIST (President Bae Choong-sik), has developed an ionic soft robot called the 'Ionograsper' that detects approaching objects and moves to grasp them when exposed to light.

The key feature of this robot is that a single soft material serves both as a sensor and as an artificial muscle. A brief exposure to weak ultraviolet (UV) light can induce movement, and after the light is turned off the deformed state is maintained for more than 10 minutes without additional energy input.

Conventional soft robots often mount sensors that detect the environment separately from the actuators that produce motion. As a result, parts and wiring increase, the structure becomes complex, and continuous energy supply may be required to move or maintain a specific posture. To reduce these limitations, the research team integrated sensing and actuation functions into a single ionic polymer material.

The mechanism for detecting an approaching object lies in the movement of ions inside the material. When an electrically charged object approaches, the surrounding electric field alters the arrangement of ions within the material, generating an electrical signal. This enables detection of an object's approach and movement without a separate sensing power source.

Motion is driven by the material's responses to light and moisture. When exposed to weak UV light, the structure of the light-responsive molecule azobenzene in the material changes and some moisture is released, forming nanoscale pores invisible to the naked eye.

In this process, the motion of polymer chains is restricted, temporarily fixing the altered internal structure. When the light is turned off, the material reabsorbs moisture at different rates on each side, causing it to bend in the opposite direction. Because the polymer structure then relaxes slowly, the deformed shape can be maintained for a certain period.

The team implemented these characteristics in the Ionograsper, modeled on the Venus flytrap's sensing and capture motions. The Ionograsper detects an approaching object and, upon UV stimulation, grasps it. It then maintains the capture state without additional energy input and naturally releases the object as the internal structure of the material gradually relaxes.

This study suggests a direction for material design applicable to physical AI robots that interact with people and objects in the real world. Applying soft materials that combine sensing and actuation to a robot's surface or joints could reduce parts and wiring and help realize flexible movement. However, this achievement represents the material and soft-robot functionality stage; the team plans to expand applications in the future by linking the material with artificial intelligence control technologies.

Professor Kim Yong-min said, "The core of this research is that a single soft material serves both as a sensor that detects surrounding objects and as an artificial muscle that generates movement," adding, "Because a short light stimulus can grasp an object and maintain it for a certain time, we expect this to help reduce a robot's structural and energy burden. Going forward, we will develop this material into one for physical AI robots that interact flexibly with people and objects by integrating it with artificial intelligence control technologies."

This research was conducted jointly with Professor Moon Hong-cheol's team at the Korea Advanced Institute of Science and Technology (KAIST). The results were published in the international journal Advanced Materials and selected as a cover paper. The paper is titled 'A Multifunctional Ionograsper Enabling Ion-Redistribution Proximity Sensing and Structural-Reconfiguration-Driven Bidirectional Actuation'.