Newswise — Artificial camouflage that imitates concealment technologies existing in the natural world, such as the ones found in chameleon and octopus, is recently attracting a great attention for various military applications in the forms of wearable devices and soft robots. However, in the previous studies, the pixelated artificial camouflage device had a disadvantage in that the concealment efficiency was considerably lowered in the background where a pattern smaller than an individual pixel was required. In addition, for practical application as a camouflage device, real-time background sensing ability is required, but this active camouflage technology has not yet been implemented due to the complexity of the required system.
Recently, Prof. Seung hwan Ko's group at Seoul National University in the Republic of Korea has developed a wearable artificial chameleon skin that can conceal itself immediately by detecting the surrounding background in real-time. By layering thermochromic liquid crystal (TLC) ink and the vertically-stacked multilayer silver (Ag) nanowire (NW) heaters, Ko's group tackled the obstacles raised from the earlier concept and developed more practical, scalable, and high-performance artificial camouflage at a complete device level.
The research group enables colorful camouflage device by incorporating TLC ink at the surface that changes light reflectance based on the device temperature, enabling the expression of various colors by changing the temperature via the Ag NW heaters. Since these vertically-stacked Ag NW network heater has a different pattern for each layer, it is possible to activate either a single layer selectively or multiple layers simultaneously to exhibit a wide range of colors and patterns.
In addition to the device's capability of high-resolution crypsis, the device has a real-time sensing system that enables blending into the background immediately. Based on this unique feature, the research group demonstrated the actual artificial chameleon robot that is capable of camouflaging into the colorful and complex background in real-time.
This research is published as a paper entitled “Biomimetic chameleon soft robot with artificial crypsis and disruptive coloration skin" in the Nature Communications. (doi.org/10.1038/s41467-021-24916-w)
Participating researchers: Hyeonseok Kim (Seoul National University), Joonhwa Choi (Seoul National University), Kyun Kyu Kim (Seoul National University), Phillip Won (Seoul National University), Sukjoon Hong (Hanyang University), and Seung Hwan Ko (Seoul National University)
This work is supported by the National Research Foundation of Korea (Nos. 2021R1A2B5B03001691, 2016R1A5A1938472).