In a study published earlier this month, researchers at the Center for Nanoscience Technology at the University of Central Florida (UCF), in the United States, created an unprecedented ink that does not use any type of pigment. Baptized as plasmonic ink, the dye uses nanoscale structural arrangements of colorless materials – aluminum and aluminum oxide – to generate ions.
According to research lead and UCF professor Debashis Chanda, a inspiration for the new ink came from the wings of butterflies. It is the first eco-friendly, large-scale, multi-color alternative to today’s pigment-based paints. The objective, says the researcher, is to contribute to global efforts to save energy, with a reduction in global warming.
Currently, the external paints of buildings have undergone technological improvements with the objective of retaining heat in the coldest regions, and keeping it outside in the hottest areas. To meet these specifications, plasmonic ink is extremely lightweight, thanks to the ink’s high area-to-thickness ratio. This allows full coloring to be achieved with an ink thickness of just 150 nanometers (0.00015 millimeters).
How does plasmonic ink work?
Structural absorption for color generation. Source: Cencillo-Abad et al.
According to the study, color engineering works by controlling the absorption or reflection response of the dye to white light. In this way, all conventional paints are composed of pigments based on light absorption mechanisms of molecules to determine their colors, that is, the non-absorbed light is reflected back and seen by the observer, who associates it with the color of the object.
In the case of the plasmonic ink developed by the research group, instead of controlling the absorption of light, these structural dyes control the way it is reflected and scattered, so much so that the constituents of the material have completely different tones, or even colorless. That is, the structural color does not depend on the chemical composition of the material, but can be observed in complex structures, such as butterfly wings.
Therefore, Chanda claims that his inspiration was nature itself, in which, in addition to butterflies, flowers, birds and underwater creatures also reveal attractive tones created solely by the geometric arrangement of colorless materials.
The study was published in the journal Science Advances,
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