Prof Peter Styring at the University of Sheffield has developed a technology which could be used to improve the speed of alpine skis, by embossing the base of the skis to reduce water adhesion. Reducing the water adhesion (or increasing hydrophobicity) has been shown to reduce the friction experienced by the ski and hence increase ski speed across snow.
The technology takes inspiration from hydrophobic surfaces in nature, such as those found on Lotus leaves. These surfaces use microscale structures such as dimples or pillars to reduce surface wetting.
Ski bases are made from ultrahigh molecular weight polyethylene (UHMWPE). Introducing microscale structures to this material presents a processing issue, since casting is not an option as the polymer degrades before its melting point. This problem has been overcome by applying heat and pressure (whilst remaining below the degradation temperature) to a steel mesh placed upon the ski base, in an embossing process (below). This pressing introduces the desired patterning to the UHMWPE.
An increased contact angle (indicating reduced surface wetting) is seen following embossing (below), indicating increased hydrophobicity and therefore increased speed of ski.
The original publication was Superhydrophobic Ski Bases for Reduced Water Adhesion. Nurul A. Nordin and Peter Styring, Procedia Eng., 2014, 72, pp 605–610.
Article by Stephen Knox; a PhD Student on the EPSRC Polymers, Soft Matter and Colloids CDT programme. For more information, please contact Dr Joe Gaunt at the Polymer Centre.