Building a Better Raincoat

With winter really kicking in, a lot of people's thoughts are turning to putting the heating on, eating more toast or working out what possessions they don't need and will burn most effectively. However, at the University of Zurich, researchers' thoughts have turned to something subtly different, much less flammable and much, much more useful: the perfect raincoat.

The team, led by Stefan Seeger, have developed a fabric made from polyester fibres and coated with countless tiny silicone filaments. These nanofilaments are chemically designed to repel water. The 'spikes' of the filaments, each no more than 4-nanometres wide, combine with a surface repel water to ensure that water hitting the material is actively repelled by it, droplets forming into spheres that can be rolled off the surface by tilting it as little as two degrees. Simply put, the garment cannot be made to stay wet, even if a fire hose is trained on it. ( So how will you wash it? - SFX )

What's really impressive is that the nanofilaments trap a layer of air between them. Known as a plastron, this layer is used by some insects to breathe underwater. It also never actually comes into contact with the polyester fabric of the coat, further ensuring that the garment simply cannot stay wet.

The plastron layer has another side effect that may make future Olympics far more interesting. It reduces drag by 20% meaning that the possibility of performance enhancing swimming costumes that never get wet has edged ever closer.

Tests on the coating - which can also be added with varying efficiency to wool, viscose and cotton - continues. So, the next time you're digging your car out of the snow whilst being lightly soaked take heart. Soon, you'll be able to do it in a coat that actually refuses to get wet.

Article contributed by Alasdair Stuart, of Hub magazine ( www.hub-mag.co.uk ).