Scientists are happy, so color them happy. At the National Institute of Standards and Technology, they studied an exotic gel that has an unexpected property.
The research team calls the material "SeedGel" and it has shown promise as a multi-purpose tool. The gel's ability as a temperature-sensitive light filter is highlighted in a new paper. Depending on the gel's temperature, only a certain wavelength of light will pass through it. The wavelength can be altered by a temperature change of less than a tenth of a degree Celsius.
The SeedGel can transform from clear to opaque and back again, but we did not explore what it could do with color. It was a new discovery.
The team's creation is different from other teams. It's not a mood ring, it's a thermochromic liquid crystal that changes color with temperature. It is not a variation on the photochromic sunglass lens. The gel works as a gate for a specific wavelength of light.
The gel begins as a transparent fluid made of water and liquid solvent. If this mix is heated to a certain temperature, the liquids and nanoparticles will form a physical gel that is transparent but has a different internal structure. The liquids form interlocking channels with the particles in one of them.
As it is heated through a specific range of higher temperatures, the newly discovered effect appears, as the gel grows opaque to all but individual colors. Once this temperature range is exceeded, the gel becomes translucent.
This behavior is explained by Neutron scattering experiments. Changing the temperature can cause an exchange of liquid between the channels. There is one wavelength of light that gets through.
The Christiansen effect was discovered in 1884. The new gel that the researchers have created is more sensitive to temperature changes than the filters that rely on the Christiansen effect, as it can be tailored to any temperature between 15 and 100. It is possible to tune it to cover a wide range of wavelengths, from ultraviolet to near-IR. It allows more light to pass through.
As the gel is made of inexpensive, readily available materials, it has advantages for industry.
He said that the manufacturing process can be scaled up. It is a promising candidate for use in a range of smart optical devices.
More information: Yuyin Xi et al, Finely tunable dynamical coloration using bicontinuous micrometer-domains, Nature Communications (2022). DOI: 10.1038/s41467-022-31020-0 Journal information: Nature Communications
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