A new ultra-black coating for automotive applications has been developed by researchers, combining traditional carbon black pigment with carbon nanotubes to achieve near-total absorption of visible light. The coating absorbs an average of 99.90% of visible light wavelengths and meets automotive industry standards for long-term stability.
Background and Development
The development follows the 2019 unveiling of a BMW concept car coated with a vertically aligned carbon nanotube (VACNT) array, which generated industry interest in ultra-black finishes for vehicles.
Zhiwei Liu, a research chemist at Nipsea Group, stated that the coating uses structural absorption to improve light absorption efficiency compared to carbon black dispersions alone. Liu noted that increasing the proportion of carbon nanotubes could further enhance light absorption, though it may reduce industrial processability.
Technical Specifications
The coating is a composite material. According to researchers, future development may focus on multi-layer coatings with gradient refractive index to reduce interface reflection. The research team has completed technical proof-of-concept for the manufacturing process. Further work is planned to verify coating application parameters and perform comprehensive film performance validations.
Broader Context of Ultra-Black Materials
Ultra-black materials—substances that absorb nearly all incident visible light—have a history spanning engineered nanostructures and natural examples.
- Engineered materials include Vantablack, made of vertically aligned carbon nanotubes, which absorbs up to 99.965% of light.
- Natural ultra-black structures have been observed in deep-sea fish, birds of paradise (with feathers reflecting as little as 0.05-0.31% of light), and butterflies, using geometric and morphological structures to trap light.
Applications
Ultra-black materials are used in multiple fields, including:
- Astronomy (reducing stray light in telescopes)
- Microscopy and camera optics (improving image clarity)
- Spectroscopy and quantum sensing (suppressing noise)
- Thermal management (in spacecraft and electronics)
- Solar thermal systems (heat absorption)
- Stealth technology (for aircraft and drones)
A separate Chinese study reported the development of durable, waterborne carbon nanotube composite coatings achieving over 99.9% absorption, described as suitable for industrial applications including automotive use.