Research teams have been studying ultrablack materials for well over a decade, exploring how biological structures trap light and how these principles might be adapted for engineered surfaces. Much of this earlier work focused on coatings for optics, carbon-nanotube arrays, and thermally stable absorbers, but the materials were often rigid, fragile, or only functioned at limited viewing angles. A group at Cornell University has now demonstrated a fabric-based alternative inspired by the feathers of the magnificent riflebird, a bird-of-paradise species known for plumage that absorbs nearly all incident light. Their approach produces what appears to be the darkest textile reported to date while retaining the flexibility and wearability expected of clothing materials.
The project, led by Larissa Shepherd in Cornell’s Responsive Apparel Design Lab, began with structural analysis of riflebird feathers supplied by the Cornell Lab of Ornithology. Researchers examined how melanin pigments and densely packed barbules work together to direct light inward rather than allowing it to reflect back. Similar mechanisms have been documented in butterflies and deep-sea fish, and these studies helped guide the Cornell group’s early experiments. Rather than relying on surface coatings alone, they combined a synthetic melanin dye with a plasma-etching process that alters the wool fibers themselves.
Jayamaha, H., Park, K., & Shepherd, L. M. (2025). Ultrablack wool textiles inspired by hierarchical avian structure. Nature Communications, 16(1), 10581. https://doi.org/10.1038/s41467-025-65649-4
The method starts with polydopamine, a melanin analogue used in a variety of bioinspired materials research. Shepherd’s group ensured that the dye penetrated the merino wool deeply so that later modifications would not expose lighter fibers. After dyeing, the textile was placed in a plasma chamber to etch away portions of the fiber surfaces. This produced nanoscale projections—short fibrils that scatter and trap incoming light by forcing it to bounce multiple times before escaping. While other ultrablack materials have used similar principles, particularly in carbon nanotube arrays grown on silicon, this is one of the few instances where the effect has been achieved in a wearable, natural fiber.
Larissa Shepherd from Cornell University stated,
“Polydopamine is a synthetic melanin, and melanin is what these creatures have. And the riflebird has these really interesting hierarchical structures, the barbules, along with the melanin. So we wanted to combine those aspects in a textile.”
Measurements showed that the treated fabric reflected roughly 0.13% of total incident light, lower than values reported for most textile-based blacks and comparable to some high-performance engineered absorbers. The group also tested reflectance at different angles and found that the ultrablack appearance remained stable over a viewing span of about 120 degrees. This consistency addresses a limitation seen in many biological ultrablack surfaces, including the riflebird itself, whose feathers appear less black when viewed off-axis. Other research groups have highlighted this angle-dependence as one of the remaining barriers for practical ultrablack applications in optics and sensing, making the textile’s performance notable.
In addition to laboratory characterisation, the team worked with a fashion design student to create a garment that incorporated the new fabric. The stability of the color made the material useful for visual demonstrations; in image adjustments where brightness and hue were altered, the ultrablack regions remained nearly unchanged. While the Cornell group stresses that the textile is still experimental, they have filed for patent protection and are considering routes to commercial development. Discussions around potential applications in solar-thermal systems, thermal camouflage, and energy-absorptive layers have been part of their early outreach, reflecting interest from both apparel and engineering communities.
The broader context of ultrablack research includes industry work on antireflective coatings for telescopes, sensors and photovoltaics. Many of these technologies rely on complex nanostructures grown through high-temperature or vacuum-based methods that are not readily adapted to flexible substrates. By working with wool, silk and cotton, the Cornell team aims to expand the range of manufacturable materials that can deliver low reflectance without specialized equipment or high energy input. Their two-step process may also offer a template for other biomimetic textiles, where natural structures provide a starting point for engineering strategies aimed at manipulating light.
Shepherd describes the project as an intersection of apparel design, materials science and bioinspired engineering. The group plans to continue studying how different fiber types respond to the etching process and how the technique scales across larger production runs. While development is still in its early stages, the work adds to an expanding research landscape exploring how natural optical structures can inform new material technologies suitable for both industrial use and everyday wear.
Adrian graduated with a Masters Degree (1st Class Honours) in Chemical Engineering from Chester University along with Harris. His master’s research aimed to develop a standardadised clean water oxygenation transfer procedure to test bubble diffusers that are currently used in the wastewater industry commercial market. He has also undergone placments in both US and China primarely focused within the R&D department and is an associate member of the Institute of Chemical Engineers (IChemE).
