'Wearable Computer' Becomes Reality... Pusan National University's Lee Geonhee and Seoul National University's Park Sungjun Lead Team to Achieve Smart Clothing Implementation

Performance Maintained After 10,000 Stretches and Machine Washing
Sewable Thickness and Strength Achieved

A joint research team from Pusan National University and Seoul National University has succeeded in developing a highly stretchable electronic fiber that is actually wearable, bringing the commercialization of wearable technology one step closer.

Pusan National University announced on May 12 that Professor Lee Geonhee's team from the Department of Optical Mechatronics Engineering, in collaboration with Professor Park Sungjun's team from Seoul National University, has developed a stretchable electronic fiber capable of continuous production up to 50 meters and has successfully implemented it in the form of actual clothing.

Professor Lee Geonhee of Pusan National University, Professor Park Sungjun of Seoul National University, PhD candidate Lee Yunheum of KAIST, PhD candidate Seo Hyunyup of KAIST. Provided by Pusan National University

This achievement was published in the online edition of the international journal Nature Communications on May 9.

Expectations for the realization of 'wearable computers' The research team focused on liquid metal (LM) particles, which are flexible and highly conductive. However, due to the material characteristics of being in a liquid state, issues such as leakage and limitations in large-area production have been pointed out as problems.

To address this, the researchers newly developed a compounding technology that encapsulates liquid metal particles with a thermoplastic polyurethane (TPU) polymer. They also applied an ultrasonic-based high-power sonication technique, which induces self-agglomeration and chemical bonding between particles, thereby creating a stable fiber structure without concerns about leakage.

Professor Lee Geonhee explained, "With this double-structured fiber that possesses both conductivity and stretchability, it is now possible to manufacture wearable devices that can be stably worn in everyday life," adding, "This will serve as a catalyst to accelerate the realization of wearable computers."

Confirmation of smart clothing potential The research team applied a Torsionally Structured Fiber Twist (TSFtw) technology so that the fiber could be used in actual sewing, precisely twisting multiple strands to secure mechanical strength and thickness. This electronic fiber maintained its performance in real-life situations such as machine washing, stretching over 10,000 times, and repeated bending.

In particular, the team used this fiber to produce intelligent digital clothing by integrating a heart rate sensor, a wireless keyboard, an IMU-based motion tracker, and an interactive display into garments, and demonstrated stable operation through experiments in various environments.

This technology is significant in that it has secured both stability and performance to the extent that functional fiber electrodes can be mass-produced on an industrial scale. It can be applied in a wide range of fields, including medical smart clothing, sports, healthcare, and military wearable equipment.

This study was conducted with Professor Lee Geonhee of Pusan National University as the first author, Professor Park Sungjun of Seoul National University as the corresponding author, and KAIST PhD candidates Lee Yunheum and Seo Hyunyup as co-first authors.