Robust hydrogels with orderly assembly of hydroxyapatite induced by temperature gradient

Hydrogels with high water content, excellent permeability, and biocompatibility are widely used in the biomedical field. In this study, an ordered structure-reinforced hydroxyapatite (HA) composite hydrogel with high water content, high strength, low friction, and fatigue resistance was developed through a molecular network design combined with temperature field-induced orientation and nano-reinforcement technology. The hydrogel has a honeycomb network with a vertically ordered orientation, showing greater network regularity, greater freedom of network cross-linking points, and enhanced flexibility and rigidity of the polymer chain. Its compressive strength is 11 MPa, compressive modulus is 5.2 MPa, friction coefficient is 0.05, and it also has excellent crack propagation and compressive fatigue resistance, exhibiting greater mechanical strength and better tribological properties. Thus, new applications of hydrogels in the biomedical field and soft biological equipment have expanded.