Phys.org June 27, 2022
A team of researchers in the US (NIST, University of Delaware) has developed a gel, they call “SeedGel’ which has the capability as a temperature-sensitive light filter. When white light is shone at the gel, depending on the gel’s temperature, only a specific wavelength will pass through it. A temperature change of less than a tenth of a degree Celsius can be enough to alter the permitted wavelength, which can be any color in the visible range as well as parts of the ultraviolet and infrared. The gel is made of water and liquid solvents with silica nanoparticles added. When the mix is heated to a certain temperature, the resulting gel possesses a different internal structure formimg interlocking microscopic channels, with the nanoparticles confined within one of them. Through neutron scattering experiments they found that changing the temperature causes an exchange of liquid molecules between the microscopic channels, altering the overall refractive index of these channels. One wavelength of light gets through, but other colors get scattered. The gel offers distinct advantages to industry as it can be customized to anywhere between 15 and 100 degrees Celsius, and tuned to cover a wide range of wavelengths, potentially from ultraviolet to near infrared. It permits more light to pass through than typical Christiansen filters…read more. Open Access TECHNICAL ARTICLEÂ
Dynamically tunable coloration of SeedGel in both scattering mode and transmission mode. Credit: Nature Communications volume 13, Article number: 3619 (2022)Â