Evaluation of lubrication property of poly(vinyl alcohol) hybrid gel for artificial articular cartilage

Poly (vinyl alcohol) (PVA) hydrogel is the candidate material for artificial cartilage. PVA hydrogels prepared by hybrid method of freeze-thawing (FT) and cast-drying (CD) method (PVA-hybrid gel) were developed, and lubrication property of PVA-hybrid gel was evaluated. Sliding pairs of an ellipsoidal PVA hydrogel and a flat glass plate were tested in reciprocating friction test. PVA-hybrid gels were prepared by temperature (T) and humidity (H) controlled drying process. Friction of PVA-hybrid gel prepared by drying process at T of 8°C and H of 80%RH gradually increased. PVA-hybrid gel prepared by drying process at T of 8°C and H of 50%RH showed low friction coefficient of 0.013 but it gradually increased with increase of sliding distance and surface damage was progressed. When the additional drying process at T of 20°C and H of 40%RH after the drying process at T of 8°C and H of 50%RH was provided, PVA-hybrid gel showed extremely low friction coefficient such as 0.006 and wear of this hybrid gel was slight. The additional drying process contributes to obtaining the surface layer of PVA-hybrid gel with low friction and low wear.