In this study we evaluate the interfacial shear strength and scratch
resistance of medical grade ultra-high molecular weight polyethylene
(UHMWPE) (GUR 1050 resin) as a function of polymer crystallinity.
Crystallinity was controlled by heating UHMWPE samples to a temperature
above its melting point and varying the hold time and cooling rates. Degree
of crystallinity of the samples was evaluated using differential scanning
calorimetry (DSC). Quantitative nanoscale friction experiments were
conducted using an atomic force microscope with commercially available
Si3N4 probes under dry conditions. A higher
crystallinity resulted in lower friction force and lower interfacial shear
strength as well as increased scratch resistance. The trend in friction
response was observed in microscale friction measurements.