Protection from chemical warfare -- and coffee stains


Published February 13, 2013


A new substance can stop any surface from getting wet, meaning it could revolutionize chemical and biological warfare protection for the military -- and lead to clothing impervious to coffee stains.

This very same nanoscale coating -- a recent discovery funded by the Air Force Office of Scientific Research -- could purify fuel and control oil and fuel leaks.

In the current Journal of the American Chemical Society, a team from the Air Force and University of Michigan has published their chemical shield discovery -- something that they claim protects “against virtually all liquids."

The innovative nanoscale coating is about 95 percent air, and when applied to a surface, the coating repels liquids and causes them to bounce off. It's applied with an electric charge that creates fine solid particles from a liquid solution, a process called “electrospinning.”

The Air Force’s liquid resistant nano-cubes made from carbon, fluorine, silicon and oxygen are incorporated into the super coating.

Beyond what it does, the coating’s texture is also important: When a liquid comes in contact with it, the liquid barely touches the surface thanks to the texture. The coating creates an air pocket web within the pores of the underlying surface.

When liquid hits the coating, droplets keep their shape, staying intact. The droplets won’t spread because the coating eliminates the contact between the surface and the liquid.

In testing, the coating worked against gasoline and various alcohols as well as chemicals that burn skin such as toxic hydrochloric and sulfuric acids. When the team tested more than 100 liquids against the special coating only two were able to beat it and penetrate it. Both of these chemicals are used in refrigerators and air conditioners.

Testing revealed it also works for repelling coffee, soy sauce and vegetable oil -- so this advance holds potential not just for defense, but for the average household as well.

Even blood, printer ink, custard and paint, “non-Newtonian” liquids whose viscosity changes depending on the force applied, could not defeat the nano-coating.

Imagine raincoats that rain will never wet, work outfits impervious to coffee or printer ink splashes, children’s clothes that will resist staining from knee scrapes to juice spills, smartphones water cannot damage.

The sheer range of potential applications in defense is also exciting. For example, the technology could be useful for self-cleaning vehicle surfaces or for chemical and biological warfare protect preventing the threats from penetrating military clothing.

The Navy could also use it, for example, to create waterproof paints to reduce drag and increase speed on ships.

For the Air Force, it could prove very useful for fuel purification and the control of oil and fuel leakages in rockets and airplanes.
