"Color Changes When Pulled?... Pukyong National University and Hanyang University Develop Advanced Textile Material"

Professor Kim Daeseok's Team Develops
Ultra-Strong Color-Changing Fiber Material
with High Resilience for Visual Sensor Applications

An advanced fiber material that changes color when stretched and possesses high resilience has been developed, attracting significant attention.

The research team led by Professor Kim Daeseok (Department of Polymer Engineering) at Pukyong National University, together with master's student Jung Yoojin from the same department and Professor Um Youngho (Department of Organic Nano Engineering) at Hanyang University, has developed a mechanochromic fiber based on Cholesteric Liquid Crystal Elastomer (CLCE).

Master's student Yoojin Jung and Professor Daeseok Kim (right). Above is Professor Youngho Um of Hanyang University. Courtesy of Pukyong National University

The elastomer material, characterized by its twisted nanostructure, exhibits a mechanochromic property where the reflected color changes as the nanostructure transforms in response to external mechanical forces. Mechanochromism is highly convenient as it can be visually detected immediately and can be used semi-permanently without power, making it valuable as a power-free visual sensor in various industries.

Among mechanochromic materials, CLCE stands out for its vivid color expression due to its precise self-assembled nanostructure. However, it has been limited in practical applications because it is highly vulnerable to strong external forces or rapid deformation.

To overcome these limitations, Professor Kim Daeseok's team succeeded in developing a CLCE-based mechanochromic fiber with ultra-high strength and rapid resilience by precisely coating CLCE onto a thermoplastic elastomer (TPE) fiber material with robust physical properties.

The team synthesized a CLCE precursor that forms a twisted nanostructure and uniformly coated it onto TPE fibers through pressure injection, enhancing both the material's physical and optical properties to a practical level.

The developed color-changing fiber demonstrated high tensile and recovery strength, recovering without elongation within a 60-100% stretch range repeated eight times per second. The team anticipates that, unlike existing CLCE materials, this fiber can be immediately applied in ultra-high-speed environments such as sportswear, mobility, and aerospace sectors.

Additionally, the research team presented results showing that by adding carbon nanofillers to TPE and adjusting its properties, various CLCE mechanochromic fibers with desired characteristics can be produced.

Example illustration of ultra-fast recovery, ultra-strong mechanochromic CLCE-TPE fibers and fabrics.

The research paper, "Ultra tough and high resilience mechanochromic fibres for real world stress detection," was published in February in an international journal, a sister publication of Nature.

Professor Kim Daeseok stated, "This study is significant in that it maximized commercial viability by developing a composite that combines with existing commercially available materials to create new properties," and added, "Just as the weak CLCE becomes powerful when equipped with TPE like an Iron Man suit, we will continue to research ways to create new functionalities centered on materials with excellent properties but weak physical strength."

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