The ice friction of polymeric substrates

A fixture has been designed and utilized in conjunction with a conventional rotational rheometer to measure and study the mechanisms of friction of polymeric surfaces (ultra-high molecular weight polyethylene, polytetrafluoroethylene and polymethylmethacrylate) on ice. Ice friction experiments were performed at various sliding velocities (from 0.0079 to 1.96 m/s), temperatures (from -25 degrees C to -1.5 degrees C), and various degrees of surface roughness. It was found that the magnitude of the sliding velocity and temperature play important roles in ice friction. Friction coefficient decreases with increasing temperature at high sliding velocities (from 0.79 to 1.96 m/s) due to surface lubrication. However, at lower sliding velocities (from 0.0079 to 0.079 m/s) the friction coefficient initially decreases and then increases due to the modification of the real contact area on the ice surface. The ice friction coefficient was found to be nearly independent of relatively small differences in surface roughness. Finally, the ice friction coefficient of three polymer substrates exhibiting very different static contact angles, from hydrophilic to hydrophobic, was found to scale inversely with their water static contact angle. (C) 2012 Elsevier Ltd. All rights reserved.