A research team led by Professor Taesung Kim from UNIST's Department of Mechanical Engineering has developed a technology that leverages nanoscale wrinkles on transparent films to reveal or hide color patterns, including traditional Korean Dancheong designs, by folding and unfolding the film.

Published in Advanced Functional Materials, this study explores a technology based on structural coloration, where nanoscale wrinkles manipulate light to create vibrant colors. Similar to how chameleons and peacocks generate blue hues without pigments, this approach utilizes nanostructures on transparent films to display or conceal patterns through folding and unfolding.

Figure 1. Nanoscale Wrinkles Enable Dynamic Color Display on Transparent Films

The researchers engineered nanostructures to form wrinkles that emerge only when the film is bent, enabling the controlled display or concealment of colors. By tuning the spacing and height of these wrinkles, they achieved a diverse range of color variations [1]. Figure 1 shows Nanoscale Wrinkles Enable Dynamic Color Display on Transparent Films.

To control wrinkle formation, the researchers designed a dual-layer film structure, where a rigid layer sits atop a flexible one. When force is applied, differences in the layers' physical properties cause nanoscale wrinkles to appear on the rigid surface. This mechanism mirrors how skin wrinkles form when pinched due to density variations between the epidermis and dermis.

By utilizing a dual p hotolithography technique, the researchers fabricated wrinkle pixels with adjustable spacing and height on a single film. The wrinkles, ranging from 800 to 2,400 nm in spacing and 100 to 450 nm in height, demonstrated the capability to generate colors spanning the entire visible spectrum.

The team also successfully incorporated Dancheong designs using wrinkle pixels, which became visible only when the transparent film was bent and disappeared when the force was removed, restoring the film's transparency.

Professor Kim highlighted that this technology enables the creation of dynamic structural colors through a simple process [2]. Unlike dye-based methods, these colors do not fade over time, making the technology ideal for anti-counterfeiting and stimuli-responsive smart displays. Additionally, the technology is being licensed to N.B.S.T., a domestic anti-counterfeiting solutions company, for commercialization.

References:

1. https://phys.org/news/2025-03-nanoscale-wrinkles-display-conceal-vibrant.html
2. https://www.lifetechnology.com/blogs/life-technology-science-news/new-technology-uses-nanoscale-wrinkles-for-color-patterns?srsltid=AfmBOorUqk4qhSpTLxzTjpH6S4zjnn38vg61V8jRQ7EE17eoXbq5ql0m

Cite this article:

Janani R (2025), Nanoscale Wrinkles on Films Reveal or Hide Vibrant Color Patterns, AnaTechMaz, pp. 169