The running surface, also known as the ski base, of a modern ski must meet three requirements at once: It should be elastic, low-wear and, above all, it should glide excellently through the snow. In the case of almost all ski manufacturers, the running surface is largely made of high-density polyethylene (HDPE), i.e. polyethylene with a high density of between 0.94 and 0.97 g/cm³. For top-class skis, fine silicate particles are also incorporated into the bases. The coating is manufactured - depending on the quality requirements - by extrusion or by sintering.
The tribology of ski-snow contact is difficult to document scientifically and is not yet fully understood. Presumably, the sliding behavior of the ski benefits if water droplets at the contact points between the coating and the snow immediately melt and freeze. However, if a continuous film of water forms in the contact area due to an excessive amount of water, the gliding properties deteriorate. Manufacturers try to compensate for this with additives such as carbon, zeolite or fluorine in the ski base.
You can read more about this in mo issue 1-2/2023 or online here!