Oil-Based Fast Ultralow Friction Achieved by Semisolid\nLubricant Domained by Poly-α-Olefins-Subnanowire–Stearic\nAcid at Steel/PTFE Interface

Liquid\nlubricants can reduce the friction and wear of two relative\nmoving surfaces. However, there are still great challenges to achieve\nanticreep and superlubricity of liquid lubricants at the same time.\nIn this study, a novel semisolid lubricant (P<sub>30</sub>SSA) was\ndesigned by fixing poly-α-olefins 30 (PAO30) base oil in a three-dimensional\nnetwork structure constructed by subnanowires (SNW) and stearic acid\n(SA), avoiding the creep problem of base oil and achieving ultralow\nfriction (0.006–0009) at steel/polytetrafluoroethylene (PTFE)\ninterfaces in a short period (∼6 s). Compared with dry friction,\nthe wear rate of the PTFE was reduced by 98%. Moreover, the friction\ncoefficient remains below 0.01 after more than 150,000 cycles. The\nultralow friction behavior is attributed to the increasing bearing\nability caused by the three-dimensional network structure in P<sub>30</sub>SSA, the reduced internal friction of P<sub>30</sub>SSA generated\nby the shear thinning of the lubricant during the friction process,\nand the physisorption film formed on the surface of friction pairs.\nThe P<sub>30</sub>SSA solves the problem of liquid lubricant creeping\nand achieves ultralow friction on the surface of steel/PTFE. This\nwork opens up a new direction for semisolid lubricants and provides\na new idea for the study of the ultralow friction mechanism.