Professor Soo-Seok Choi's team—EE doctoral students Sang-Hyun Han (first author), Jun-Hyuk Shin and Ji-Yoon Park, master's student Hak-Jun Yang and postdoctoral researcher Seung-Min Nam—developed the first method to precisely measure fine structural characteristics throughout the stretching of serpentine structures and visualize them directly in color. The study was published online in Advanced Science (IF 14.3) and selected for its inside back cover.
Stretchable technology, with deformability approaching paper or fabric, is regarded as an ultimate flexible technology. Worldwide interest has surged because of applications and possibilities beyond existing technology: displays, sensors, semiconductors, artificial electronic skin, robotics, smart clothing, encryption, smart cars, electromagnetic-wave control, communications and fashion.
Commercial stretchable technology requires stretchable interconnects that allow rigid devices such as LEDs and semiconductors to extend through winding structures. Serpentine interconnect development is therefore fundamental. Performance depends on precise shape design and understanding behavior throughout the complex stretching process. Previously, accurate evaluation during deformation was unavailable; failure could be detected only when the structure broke, with interpretation largely limited to theoretical simulation. This has been a major obstacle to broader commercialization.
The team developed a method to evaluate and intuitively visualize serpentine interconnect behavior throughout complex, fine-scale stretching. They created structural color from periodic dielectric nanostructures in a rubber-like stretchable elastomer. Its mechanochromic response changes color across the visible spectrum as it stretches. The color directly visualizes the entire stretching process, while quantitative measurement of wavelength changes reveals the structure's behavior.
The method shows what microscopic serpentine shapes should be designed for different stretching environments. Its research value lies in enabling accurate analysis of stretchable structures and complex deformation, opening paths to broader applications and commercialization. Support came from the Samsung Science & Technology Foundation and the Korea Evaluation Institute of Industrial Technology's stretchable display and stretchable demonstration technology development programs.