Advances on Hydrogel Lubrication Modification Under Diverse Design Strategies

Hydrogel is a new type of lubricating material, and its lubrication performance is influenced by factors such as water content, chemical structure, cross-linking density, and friction pair materials. Currently, research on the lubrication performance of hydrogels has not formed a unified standard and system. Given that the lubricity of hydrogels mainly depends on their components and structure, as well as the chemical interactions between the polymer chains of the hydrogel network and the friction interface, this review systematically discusses the diverse design strategies of hydrogel lubricants based on the hydration and boundary lubrication mechanisms of gels, while elucidating the underlying enhancement mechanisms, as well as the corresponding tribological behavior and applications for different strategies. Finally, the main challenges and future research directions are underlined, aiming to provide theoretical and technical support for the design optimization and practical application of advanced hydrogel lubrication materials.