Darth Vader would have loved to wear a suit made from a fabric inspired by the feathers of the magnificent riflebird—a bird of paradise native to New Guinea and the northern tip of Australia. According to its inventors, this fabric is the darkest ever created, absorbing 99.87% of incoming light. The scientists call it Ultrablack Wool.
The fabric, made from white merino wool, is dyed with polydopamine, an artificial form of melanin, which gives skin, hair, and eyes their natural color. It is then etched in a plasma chamber to make microscopic, pointed structures called “nanofibrils”. These structures trap light very effectively.
“I’ve had professors come in when we were working on this, and they went, ‘It’s like looking at a black hole,’” said Larissa Shepherd, an assistant professor in the Department of Human Centered Design at Cornell University in New York, and senior author of a study about the new fabric, published in the journal Nature Communications.
Keeping in mind the visual pleasure of the riflebird’s plumage, the scientists have made a prototype dress using this fabric. However, unlike the riflebird’s feather, which appears ultrablack only when viewed head-on and shiny otherwise, this fabric remains ultrablack when viewed at an angle of 120 °.
The etching process is key to reaching this broad angular spectrum. The etching process roughens the fibers using an electrically charged gas, traps light by making it reflect, and prevents its escape.
These materials are known as ultrablack materials and typically absorb more than 99.5% of light. The most famous of these materials is the Vantablack coating, which can absorb 99.97% of visible light. Primarily used in cameras and telescopes, this material is made from microscopic carbon filaments. Unlike Vantablack, Ultrablack Wool is wearable, less expensive, and easier to produce. Since this fabric uses just wool and polydopamine, which is cheaper than producing the microscopic filaments of carbon as in Vantablack, it makes Ultrablack Wool pocket-friendly.
Riflebirds get their deep black tint from melanin-rich, hair-like barbules that deflect light inwards. Many species of fish and butterflies have ultrablack shades too.
Ultrablack fabrics have existed before, too, but they didn’t match the breathability and flexibility of Ultrablack Wool. The scientists initially intended to use silk; however, they chose wool instead, as it combines better with polydopamine dye.
In addition to its visual properties, Ultrablack Wool also exhibits thermoregulatory properties. The intense black hue absorbs more sunlight when exposed outdoors, warming the fabric and the body more quickly. However, by limiting the fabric in areas of the body where we sweat most, such as the shoulders and back, we can exploit evaporative cooling. The water droplets in sweat absorb the body’s heat to vaporize, thereby vaporizing and cooling the body. This forms the basis for how athleticwear helps athletes cool.
Scientists worldwide have hailed Ultrablack Wool as a novel, innovative approach to biomimicry, the practice of replicating features of other organisms to develop new technologies. The use of a melanin-like compound as a black dye has improved the fabric’s design, as it is half as thick as other ultrablack fabrics.
However, washability remains an issue, as the dye’s performance is somewhat compromised after washing. The plasma treatment may also pose a barrier to mass production. This fabric may represent a major leap forward in athletic wear and in the design of military camouflage.
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