PVA/silica/mucin hydrogel with high toughness and low friction

For hydrogel applied in joint cartilage replacement, achieving both high toughness and low friction performance is a significant challenge. This study modifies polyvinyl alcohol hydrogel by using wet annealing and immersion methods. Wet annealing allows conformational rearrangement to improve crystallinity while maintaining the overall structure of the hydrogel. The immersion method induces the formation of tiny silica dioxide particles within the hydrogel. The mechanical properties of the hydrogel are greatly enhanced through the synergistic effect of these two mechanisms. Additionally, the introduction of mucin into the hydrogel achieves ultra-low lubrication performance through the brush-like oligosaccharide side chains and the negative charge saliva residues of mucin. The prepared hydrogel material not only exhibits excellent mechanical properties (tensile strength 5.11 MPa, tensile modulus 4.56 MPa, compressive strength 27.56 MPa, compressive modulus 2.04 MPa), but also maintains continuous lubrication and a low friction coefficient (0.037) under high loads (5 N) and high speeds (20 mm/s). The hydrogel maintains volume stability in a simulated body fluid environment for an extended period after swelling equilibrium. This method for preparing ultra-tough and lubricating hydrogels can offer valuable insights for researchers in the field.