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Polyvinyl alcohol (PVA) hydrogel is considered the most promising candidate for artificial cartilage because of its good lubricity and low permeability. However, the efficacy of single-network PVA hydrogels under variable loads has not yet been determined. In this study, a one-step physical-cross-linking method was used to compose PVA/PEG double-network composite hydrogels. We changed the polyethylene glycol (PEG) content of the composite gel and tested the frictional-wear performance under different loads and speeds. With the mass fraction of PEG at 30 wt.%, the hardness of the PVA/PEG composite gel increased to 167.7% that of pure PVA. Under dry-friction conditions, the average coefficient of friction was approximately 0.14 and the wear rate on the surface of the hydrogel was insignificant. The cross-linking between PVA and PEG greatly enhanced the stability of the composite hydrogel polymer network. The structure of the composite gel was analyzed by a variety of standard methods. The hydrogel has excellent biocompatibility and self-healing ability and is a self-lubricating, self-healing candidate material for articular-cartilage repair.

Polyvinyl alcohol (PVA) hydrogels have potential applications in bionic articular cartilage due to their good biocompatibility and low friction. However, the lack of adequate mechanical properties is a key obstacle for PVA hydrogels to replace natural cartilage. In this study, polyethylene glycol (PEG) was introduced into the PVA hydrogel, and the (PVA/PEG) composite gels were prepared by a blending physical cross-linking method. The PVA/PEG gels were treated with a simple and novel organic solvent immersion dehydration to improve its mechanical and tribological properties. And the using of organic solvents for dehydration changed the network structure of the PVA/PEG gels, which improved the mechanical properties effectively. In this study, the effects of different organic solvents on the tribological properties, swelling ratio, shore hardness, and dehydration rate of PVA/PEG hydrogels were investigated. Compared with natural drying, organic solvent dehydration reduced the gel formation time. Notably, the organic solvent dehydration treatment reduces the wear rate of PE ball friction pair to 27.4% of the original amount, improving wear resistance. Meanwhile, self-healing and cellular immune assays demonstrated the excellent biocompatibility and self-healing ability of the PVA/PEG gels.This study provides a new candidate material for the design of articular cartilage, which is expected to advance the progress of artificial cartilage repair.

Poly(vinyl alcohol) (PVA) hydrogels have shown potential applications in bionic articular cartilage due to their tissue‐like viscoelasticity, good biocompatibility and low friction. However, their lack of adequate mechanical properties is a key obstacle for PVA hydrogels to replace natural cartilage. In this study, poly(ethylene glycol) (PEG) and glycerol were introduced into PVA, and a PVA/PEG–glycerol composite hydrogel was synthesized using a mixing physical crosslinking method. The mechanical properties, hydrophilicity and tribological behavior of the PVA/PEG–glycerol hydrogel were investigated by changing the concentration of glycerol in PEG. The results showed that the tensile strength of the hydrogel reached 26.6 MPa at 270% elongation at break with 20 wt% of glycerol plasticizer, which satisfied the demand of natural cartilage. In addition, the excellent hydrophilicity of glycerol provides good lubricating properties for the composite gel under dry friction. Meanwhile, self‐healing and cellular immunity assays demonstrated that the composite gel could have good self‐healing ability and excellent biocompatibility even in the absence of external stimuli. This study provides a new candidate material for the design of articular cartilage, which has the potential to facilitate advances in artificial joint cartilage repair. © 2022 Society of Industrial Chemistry.

New surface treatments are required to improve the resistance of high-voltage aluminium conductors to corrosion and wear. This paper describes the preparation of ceramic coatings on the surface of aluminium wires by the micro-arc oxidation (MAO) technology. The surface morphology, mechanical and tribological properties, electrical resistivity, wear and corrosion resistance of the MAO-treated aluminium samples are examined and compared not only with the untreated samples but also between the use of different current densities in the MAO process. The MAO treatment can increase the tensile strength of the wire and mitigate the wire elongation at excessive high temperature. In addition, the increased surface hardness and the overlapping micro-porous distribution of the MAO coating improve the resistance of the treated sample to wear and corrosion respectively, protecting the aluminium substrate from the joint effects of wear and corrosion. Furthermore, the MAO coating has little impact on the electrical resistivity of aluminium conductors and can mitigate the resistivity change due to corrosive damage. The MAO technology providing a potential idea for the surface treatment of aluminium conductors is expected to extend the service life and alleviate maintenance needs of aluminium conductors operating in harsh environments.