PVA/PAAm hydrogel-on-titanium alloy with high bonding strength and low friction as articular cartilage replacement

Tough bonding and low friction are required for the candidate artificial articular cartilage materials. Inspired by the soft-on-hard composite structure of natural cartilage, polyvinyl alcohol/polyacrylamide (PVA/PAAm) hydrogel-on-titanium alloy was prepared by a casting-drying method to combine the excellent lubrication of soft hydrogel and the high load-bearing capacity of rigid substrate. The influences of PVA: PAAm mass ratio and swelling on the interfacial toughness of PVA/PAAm hydrogel-on-titanium alloy were evaluated by the 90° peeling test, and the friction property was investigated as a function of PVA: PAAm mass ratio, lubricating medium, and load. The results show that the interfacial toughness of PVA/PAAm hydrogel-on-titanium alloy ranges from 150 N m⁻¹ to 400 N m⁻¹ in dry state, while the interfacial toughness decreases significantly after swelling in deionized water for 24 h. The friction coefficient of PVA/PAAm hydrogel-on-Ti6Al4V alloy is ~ 0.15 when PVA: PAAm mass ratio is 1:2 under fetal bovine serum lubricating. The polyvinyl alcohol/polyacrylamide (PVA/PAAm) hydrogel-on-titanium alloy configuration provide a new strategy for the design of soft-on-hard cartilage replacement with tough bonding and low friction.