Self-healable polyacrylic acid-polyacrylamide-ferric ion dual-crosslinked hydrogel with good biotribological performance as a load-bearing surface

Although having been widely investigated, polymer hydrogels still have many defects like poor tribological properties and insufficient durability, hindering their further applications in biomedical fields. In this study, we present a simple method to synthesize polyacrylic acid-polyacrylamide-ferric ion (PAA-PAAm-Fe³⁺) dual-crosslinked hydrogels with self-healing abilities and “soft-hard” hydrogel-polyetheretherketone (PEEK) combined load-bearing surfaces with low friction coefficients. After analytical characterizations, the results demonstrated that the hydrogels could repair themselves without any external stimuli. Because of the excellent biphasic and aqueous lubrication provided by the hydrogel layer and the load-bearing capacity provided by the PEEK substrate, the friction coefficient of a load-bearing surface was as low as 0.048 in water, much lower than a pristine PEEK block or a hydrogel block sample. This work fabricated self-healable PAA-PAAm-Fe³⁺ hydrogels and low friction bearing surfaces, successfully improving the tribology properties of hydrogels, hopefully promoting their applications as biomedical materials such as articular cartilage. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48499.