Color shifts at nanoscale: Researchers develop real-time visualization system to observe stretchable technology

A research team at POSTECH has developed a breakthrough technology that analyzes in real-time the deformation of "serpentine" structures, a critical component of stretchable technology, and visualizes the process through color changes.

The team, led by Professor Su Seok Choi from the Department of Electrical Engineering, included doctoral candidates Sanghyun Han, Junho Shin, Jiyoon Park, and master's students Hakjun Yang and Seungmin Nam. The study was published in the December online edition of the journal Advanced Science.

Flexible and deformable electronics have advanced beyond bendable, foldable, rollable, and slidable designs to fully stretchable systems that allow freeform deformation. Stretchable technology is gaining traction in diverse fields, such as displays, sensors, semiconductors, electronic skin, biomimetic robots, and smart clothing.

Stretchable technology largely relies on two approaches: creating elastic materials similar to rubber and designing stretchable structures that integrate seamlessly with existing semiconductor, display, electrode, and sensor technologies. In structural stretchable technology, the serpentine interconnect—a wavy, elastic connection—plays a crucial role in providing elasticity to non-stretchable electronic components. Advancing this technology requires a thorough understanding of the structural characteristics and deformation processes during all stages of stretching.

Visualizing deformation of serpentine structures in real time

Until now, analyzing deformation in serpentine structures was only possible after physical damage, such as breaks, had occurred. This meant researchers had to rely on theoretical simulations or limited observational data from previous stretching cycles, hindering real-time insights into structural behavior.

The POSTECH team tackled this challenge by leveraging changes in structural color—color shifts that occur at the nanoscale during deformation. Using Chiral Liquid Crystal Elastomer (CLCE), a mechanochromic material that changes color when stretched, they developed a system that enables precise, real-time visualization of deformation in serpentine structures. Furthermore, the team validated the results through theoretical finite element analysis, confirming the technology's potential for optimized design applications.

Technological and industrial significance

This innovative approach eliminates the need for complex nanofabrication processes and provides a clear, real-time understanding of how serpentine structures deform. By offering actionable design guidelines for optimizing these structures in diverse stretching environments, this technology is poised to fast-track the commercialization of stretchable devices.

Professor Choi remarked, "This research opens the door to precise evaluation and design of the connection structures central to stretchable technology."

He added that the findings are expected to broaden applications and accelerate commercialization in fields such as displays, semiconductors, sensors, electronic skin, smart clothing, and soft robotics.