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.
When metal atoms form small clusters of a particular size, they show interesting and potentially useful electromagnetic characteristics, which are different from those of the actual bulk metal. To fully explore the potential of these properties, it is necessary to find ways to assemble precise macroscopic structures out of these clusters.Lire la suite