Self-lubricating and wear self-healing of polymer composites reinforced with bifunctional mesoporous silica nanocontainers

Polymer-based self-lubricating materials with self-healing ability can overcome the problems of short life-span caused by external damage during friction. This paper proposes a new bifunctional mesoporous silica nanocontainer (Cu/LO@SNF) to enhance the wear self-healing and friction-reducing properties of polymer materials. Using mesoporous silica nanoflowers (SNF) as nanocontainers, Cu nanoparticles as solid lubricant additives, and linseed oil (LO) as an external healing agent. Due to silica nanoflowers' large radial pore structure, their use for loading Cu nanoparticles can effectively prevent nanoparticle aggregation. Meanwhile, silica nanoflowers can also store a large amount of LO. Cu/LO@SNF were combined with epoxy resin (EP) to endow the resin with excellent wear self-healing and anti-wear capabilities. The results of the frictional performance test indicate that the friction coefficient of EP containing 10   wt% Cu/LO@SNF can be as low as 0.085, and the wear rate is reduced by 97.8% compared with pure EP. During the friction process, Cu NPs and linseed oil stored in silica nanocontainers are released into the contact area of the friction pair. The Cu NPs enhance tribological properties as effective lubricants and aid in repairing wear areas when used with linseed oil. The synergistic effect of Cu NPs and LO enables the wear self-healing rate of the EP to reach 77%, effectively improving the service life of EP materials.