The frictional behavior of UHMWPE films with different surface energies at low normal loads

The relationship between initial coefficient of friction, μi and surface energy (or attractive force) for ultra-high molecular weight polyethylene (UHMWPE) film is modeled and experimentally measured at low normal loads (15–75 mN). The results show that the initial coefficient of friction increases exponentially with increasing attractive force between a silicon nitride ball and visco-elastic soft UHMWPE film. There is a strong influence of the normal load on this relationship for the polymer surface in the above-mentioned load range. The magnitude of the initial coefficient of friction decreases for UHMWPE film in the higher normal load regime because of its visco-elastic and soft nature as earlier proposed by Bowden and Tabor.