In situ zwitterionic supramolecular gel lubricants for significantly improved tribological properties

We report a new type of zwitterionic gelator, which cannot only gelate base lubricating oils by supramolecular self-assembly, but be used as additive in oils for significantly improved the tribological performances. The self-assembly mechanism is confirmed by NMR. The as-prepared zwitterionic gels have good thermoreversible and thixotropic characteristics, which make them as potential high performance semi-solid lubricants. The tribological results showed that the gel lubricants possessed excellent friction-reducing and anti-wear properties compared with blank 500SN and Li-base grease with 2 wt% MoS₂. The morphologies of the worn surfaces were analyzed by scanning electron microscope (SEM). The lubrication mechanism is proposed according to in-situ electrical contact resistance and the surface composition analysis at the worn surfaces.