Darkest Black...

Image Source: CNET: Sci-Tech

Topics: Carbon Nanotubes, Materials Science, Nanotechnology, Optics

The Science of Vantablack

The name Vantablack® stands for Vertically Aligned Nanotube Array black.

Vantablack is a free-space coating consisting of a 'forest' of aligned and equally spaced, high aspect-ratio carbon nanotubes (CNTs).

The CNT array is patterned and spaced to allow photons to enter. Most of the light, or radiation arriving at the surface enters the space between the CNTs, and is repeatedly reflected between tubes until it is absorbed and converted to heat. This heat (largely undetectable in most applications) is conducted to the substrate and dissipated. The Vantablack array is very largely free-space; the volume of CNTs only makes up about 0.05% of the coating. Consequently, only a minuscule proportion of the incident radiation is able to hit the tip of a CNT, explaining why such a small amount is reflected back to the observer.

Vantablack's exceptional properties

Ultra low reflectance - Vantablack absorbs 99.965% of light (750nm wavelength)

UV, Visible and IR absorption - Absorption works from UV (200-350 nm wavelength), through the visible (350-700nm) and into the far infrared (>16 microns) spectrum, with no spectral features.

Very high front to back thermal conduction - excellent for Black Body calibration sources

Super hydrophobic - Unlike other black coatings, water has no impact on the optical properties

Very high thermal shock resistance - Repeatedly plunging a Vantablack coated substrate into liquid Nitrogen at -196°C and then transferring to a 300°C hot plate in air does not affect its properties.

Resistant to extreme shock and vibration - Independently tested, Vantablack has been subjected to severe shocks and vibration simulating launch and staging.

Information Source: Surrey Nanosystems