August 29, 2008

Military Technology Makes Almost Anything Waterproof

A former military technology can make almost any surface or fabric waterproof but remain breathable.

Originally, the process was developed to ensure soldiers' clothing remained impermeable to chemical weapons.

Now the developers of the process have signed a deal with shoemaker Hi-Tec to use the technology to waterproof many of its shoes.

This week was the first commercial debut of the treated shoes in London.

The Ministry of Defence funded the technology and it was developed at its Defence Science and Technology Laboratory for making military clothing resistant to nerve agents.

The process, known as "Ëœion masking', works by using a chemical based on the element fluorine. In a closed chamber, the chemical is vaporized and attaches, molecule by molecule, to all the fibers in a fabric, making the surface "hydrophobic" or water-repelling, so that instead of water spreading out it forms droplets on the surface.

The chemical coating covers just the fibers, rather than forming a "skin" across the whole surface, as with currently available waterproofing treatments. That means the spaces between fibers remain open and the fabric is still breathable.

Ian Robins, business development director of P2i, the company marketing the process, said the normal way to make a shoe waterproof is by putting a membrane inside the shoe such as Gore-Tex.

"That's effectively putting a plastic bag inside the shoe. No water gets inside your shoe, but at the same time that reduces the breathability both in terms of sweat and of heat escaping."

P2i claims shoe fabric made with the ion-mask process was tested for breathability in an air-flow test, outperforming commercial waterproof fabrics such as Gore-Tex by more than a factor of 100.

During the testing, the shoes were subjected to flexing and wear tests, and maintained their breathable waterproof properties even after 100,000 flexes.

P2i says the fabrics are also inherently stain-resistant and easier to clean.

"Coating a pair of shoes using the ion-mask process requires just a tenth of a gram of the fluorine compound, and costs in the region of a few dollars - significantly less than the cost of integrating membranes like Gore-Tex into a pair of shoes," said Dr. Robins.

He said the process can easily be applied to any garments or any material, and suggests that it might also become the basis for a separate after-purchase service business, like dry cleaning. It can also be used to waterproof outdoor gear.

"This could change waterproof footwear as we know it," said Michelle Swan, a senior footwear buyer at Black's Leisure Group.


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