5EA set to skyrocket, page-311

Boron Nitride (nanotubes) again, hexagonal type, as called out by Anthony Hall around 8:25 in the Investor Webcast today

World's whitest paint now thinner than ever, ideal for vehicles

Date: October 3, 2022
Source: Purdue University
https://www.sciencedaily.com/releases/2022/10/221003152158.htm
Summary:
The world's whitest paint is now thinner and lighter than ever before. This makes it ideal for cooling vehicles like airplanes or cars, which reduces the reliance on air conditioning.
The world's whitest paint -- seen in this year's edition of Guinness World Records and "The Late Show With Stephen Colbert" -- keeps surfaces so cool that it could reduce the need for air conditioning. Now the Purdue University researchers who created the paint have developed a new formulation that is thinner and lighter -- ideal for radiating heat away from cars, trains and airplanes.

The original world's whitest paint used nanoparticles of barium sulfate to reflect 98.1% of sunlight, cooling outdoor surfaces more than 4.5°C below ambient temperature when applied as a layer of paint at least 400 microns. Fine for buildings but not for applications that have precise size and weight requirements, the paint needed to be thinner and lighter.

The latest formulation is a nanoporous paint incorporating hexagonal boron nitride as the pigment, a substance mostly used in lubricants. This new paint achieves nearly the same benchmark of solar reflectance (97.9%) with just a single 150-micron layer of paint.

The paint also incorporates voids of air, which make it highly porous on a nanoscale. This lower density, together with the thinness, provides another huge benefit: reduced weight. The newer paint weighs 80% less than barium sulfate paint yet achieves nearly identical solar reflectance.

Paper:
Thin layer lightweight and ultrawhite hexagonal boron nitride nanoporous paints for daytime radiative cooling https://www.cell.com/cell-reports-physical-science/fulltext/S2666-3864(22)00352-6?