Optimizing lubrication in step slider bearingsJing, Zhaogang (Avtor) Dong, Haoyu (Avtor) Jin, Wei (Avtor) Guo, Feng (Avtor) Kalin, Mitjan (Avtor) Li, Ziying (Avtor) Wang, Dong (Avtor) Ju, Chao (Avtor) oiliness additivessurface adsorption filmsstep slider bearingoptical interferometryfilm thicknessinterfacial slipThis study examines how the molecular structures of oiliness additives affect the lubrication performance of a step slider bearing. Here an optical step-slider-on-disc tribometer was used to measure interferometric film thickness together with friction force under the present test conditions. Seven representative molecules (undecanedioic acid, undecanoic acid, palmitic acid, stearic acid, oleic acid, oleylamine and oleyl alcohol) were each blended into PAO8 at 0.15 wt% to separately probe headgroup polarity, alkyl-chain length, saturation and the number of polar heads. Compared with neat PAO8, every formulation produced a thicker film (up to 106% increase) and a lower coefficient of friction (up to 65.9% reduction), with stearic acid delivering the best overall improvement. To interpret the trends, wettability of the step-slider surface after lubricant treatment was assessed by deionized-water contact-angle measurements. The observed inlet–outlet wetting asymmetry is consistent with a possible asymmetry in interfacial slip, which may contribute to the experimentally observed combination of film-thickness increase and friction reduction.20262026-06-12 13:36:54Članek v reviji183418UDK: 539.92:539.37:669.14ISSN pri članku: 0301-679XDOI: 10.1016/j.triboint.2026.112134COBISS_ID: 278637315sl