Cartilage is well lubricated over a lifetime and this phenomenon is attributed to both of the surface hydration lubrication and the matrix load-bearing capacity. Lubricious hydrogels with a layered structure are designed to mimic cartilage as potential replacements. While many studies have concentrated on improving surface hydration to reduce friction, few have experimentally detected the relationship between load-bearing capacity of hydrogels and their interface friction behavior. In this work, a bilayer hydrogel, serving as a cartilage prototype consisted of a top thick hydrated polymer brush layer and a bottom hydrogel matrix with tunable modulus was designed to investigate this relationship. The coefficient of friction (COF, μ) is defined as the sum of interfacial component (μ_Int) and deformation/hysteresis component (μ_Hyst). The presence of the top hydration layer effectively dissipates contact stress and reduces the interface interaction (μ_Int), leading to a stable and low COF. The contribution of mechanical deformation (μ_Hyst) during the sliding shearing process to COF can be significantly reduced by increasing the local mechanical modulus, thereby enhancing the load-bearing capacity. These results show that the strategy of coupling surface hydration layer with a high load-bearing matrix can indeed enhance the lubrication performance of hydrogel cartilage prototypes, and implies a promising routine for designing robust soft matter lubrication system and friction-control devices.

软骨在一生中都得到良好的润滑，这种现象归因于表面水化润滑和基质承载能力。具有分层结构的润滑水凝胶旨在模仿软骨作为潜在的替代品。虽然许多研究都集中在改善表面水合作用以减少摩擦，但很少有人通过实验检测水凝胶的承载能力与其界面摩擦行为之间的关系。在这项工作中，设计了双层水凝胶作为软骨原型，由顶部厚的水合聚合物刷层和具有可调模量的底部水凝胶基质组成，以研究这种关系。摩擦系数 (COF, μ ) 定义为界面分量 ( μ _Int ) 和变形/滞后分量 ( μ _Hyst ) 之和。顶部水化层的存在有效地消散接触应力并减少界面相互作用（μ _Int），从而获得稳定且低的摩擦系数。通过提高局部机械模量，可以显着降低滑动剪切过程中机械变形（ μ _Hyst ）对COF的贡献，从而提高承载能力。这些结果表明，表面水化层与高承载基质的耦合策略确实可以增强水凝胶软骨原型的润滑性能，并为设计稳健的软物质润滑系统和摩擦控制装置提供了一种有前途的常规。