Although the darkest material in the world using carbon nanotubes, Venta Black absorbs more than 99.9% of light and is applied as a new material for the interior wall of a telescope or camouflage because the surface irregularities or depths applied to it are unknown. In contrast to this Venta Black, a paint that reflects more than 95% of light has been developed and attracts attention.
It emits heat energy in the form of electromagnetic waves around a hot object, causing radiant cooling to lower the temperature. It is pointed out that this radiation cooling affects the heat island and global warming. How to suppress the temperature rise caused by direct sunlight has been a challenge for a long time.
The paint developed by the Purdue University research team is a kind of acrylic paint containing calcium carbonate. Whereas existing paints only reflect 80-90% of the maximum light, the new paints reflect 95.5% of direct sunlight. Therefore, the object coated with this paint can not be heated in direct sunlight, but can maintain a temperature lower than the ambient temperature outdoors.
If you look at the painted object with an infrared camera that can measure the temperature, it is lower than the ambient temperature. The research team conducted a field test for 2 days according to various places and weather conditions, and said that the part where the new paint was applied is 10 degrees lower than the ambient temperature at night and 1.7 degrees during the day.
According to the research team, the new paint is resistant to abrasion and heat when dried by painting it in much the same way as the existing product, and can withstand at least three weeks in an outdoor environment. It also proposes combining a fluorocarbon-based polymer to increase paint durability.
The new paint manufacturing process is compatible with existing products, and manufacturing costs can be roughly the same. The paint name has not been decided yet. The research team says that developing a reliable solution for environmental radiation cooling in a practical single-layer particle matrix paint is a persistent research task. The new paint is an important player in mitigating the effects of global warming through wide application of radiation cooling. Related information can be found here .