Investigations of Polymethacrylate Tribochemical Films Using X-Ray Spectroscopy and Optical Profilometry


This study investigates the elemental composition and surface morphology of solid tribochemical films formed on steel surfaces. The reversible addition-fragmentation chain transfer (RAFT) method was used to synthesize nine different metal-free polymers, which were blended into commercial base oils. The polymers were either homopolymers of dodecyl methacrylate and ethylhexyl methacrylate or were co-polymers of these monomers with six polar monomers. After tribological testing at 100 °C using the ball-on-flat geometry, the resulting tribochemical films were imaged using scanning electron microscopy (SEM) and optical microscopy. The resulting tribochemical films have thicknesses around 50–100 nm. Two of the films corresponding to small (P1—imidazole-containing copolymer) and large (P3—less polar homopolymer) wear were cross-sectioned using focused ion beam (FIB) and analyzed for elemental composition using energy-dispersive X-Ray (EDX) mapping. Oxygen and nitrogen enrichment was observed, consistent with the relative chemical composition of the precursor polymers. Transmission electron microscopy (TEM) evidence suggests that at the worn surface, some organic elements penetrate or are mixed into the steel substrate giving an interlocking appearance. The two samples examined with TEM showed that P1 tribofilm is diffused or mixed with the steel substrate more so than P3, suggesting a stronger affinity and contact during tribofilm formation.

Graphic Abstract

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Data Availability

Optical and profilometry images (gold-coated and uncoated) and EDS mapping of all tribochemical films are available to download from the Supporting Information, free of charge.


  1. 1.

    Bardasz, E.A.: Lubricant Additives and Their Functions. ASM Handbook. Friction, Lubrication, and Wear Technology, vol. 18, pp. 135–149. ASM International (2017)

  2. 2.

    Tang, Z., Li, S.: A review of recent developments of friction modifiers for liquid lubricants (2007–present). Curr. Opin. Solid State Mater. Sci. 18, 119–139 (2014)

    CAS  Article  Google Scholar 

  3. 3.

    Spikes, H.: Friction modifier additives. Tribol. Lett. 60, 5 (2015)

    Article  Google Scholar 

  4. 4.

    Guegan, J., Southby, M., Spikes, H.: Friction modifier additives, synergies and antagonisms. Tribol. Lett. 67, 83 (2019)

    Article  Google Scholar 

  5. 5.

    Spikes, H.: The history and mechanisms of ZDDP. Tribol. Lett. 17, 469–489 (2004)

    CAS  Article  Google Scholar 

  6. 6.

    Erdemir, A.: Review of engineered tribological interfaces for improved boundary lubrication. Tribol. Int. 38, 249–256 (2005)

    CAS  Article  Google Scholar 

  7. 7.

    Korcek, S., Jensen, R.K., Johnson, M.D., Sorab, J.: Fuel efficient engine oils, additive interactions, boundary friction, and wear. Tribol. Ser. 36, 13–24 (1999)

    CAS  Article  Google Scholar 

  8. 8.

    Ueda, F., Sugiyama, S., Arimura, K., Hamaguchi, S., Akiyama, K.: Engine oil additive effects on deactivation of monolithic three-way catalysts and oxygen sensors. SAE Trans. 332–341 (1994).

  9. 9.

    Bodek, K.M., Wong, V.V.: The effects of sulfated ash, phosphorus and sulfur on diesel aftertreatment systems—a review. SAE Technical Paper; (2007).

  10. 10.

    Wright, R.A., Wang, K., Qu, J., Zhao, B.: Oil-soluble polymer brush grafted nanoparticles as effective lubricant additives for friction and wear reduction. Angew. Chem. 128, 8798–8802 (2016)

    Article  Google Scholar 

  11. 11.

    van Ravensteijn, B.G., Bou Zerdan, R., Seo, D., Cadirov, N., Watanabe, T., Gerbec, J.A., Hawker, C.J., Israelachvili, J.N., Helgeson, M.E.: Triple function lubricant additives based on organic–inorganic hybrid star polymers: friction reduction, wear protection, and viscosity modification. ACS Appl. Mater. Interfaces 11, 1363–1375 (2018)

    Article  Google Scholar 

  12. 12.

    Singh, R.K., Kukrety, A., Kumar, A., Chouhan, A., Saxena, R.C., Ray, S.S., Jain, S.L.: Synthesis, characterization, and performance evaluation of N, N-Dimethylacrylamide–alkyl acrylate copolymers as novel multifunctional additives for lube oil. Adv. Polym. Technol. 37, 1695–1702 (2018)

    CAS  Article  Google Scholar 

  13. 13.

    Upadhyay, M., Karmakar, G., Kapur, G.S., Ghosh, P.: Multifunctional greener additives for lubricating oil. Polym. Eng. Sci. 58, 810–815 (2018)

    CAS  Article  Google Scholar 

  14. 14.

    Biresaw, G., Bantchev, G.B., Harry-O’Kuru, R.E.: Biobased poly-phosphonate additives from methyl linoleates. Tribol. Trans. 62, 428–442 (2019)

    CAS  Article  Google Scholar 

  15. 15.

    Yamada, S., Fujihara, A., Yusa, S.I., Tanabe, T., Kurihara, K.: Confined film structure and friction properties of triblock copolymer additives in oil-based lubrication. Polym. J. 51, 41–49 (2019)

    CAS  Article  Google Scholar 

  16. 16.

    Robinson, J.W., Zhou, Y., Qu, J., Bays, J.T., Cosimbescu, L.: Highly branched polyethylenes as lubricant viscosity and friction modifiers. React. Funct. Polym. 109, 52–55 (2016)

    CAS  Article  Google Scholar 

  17. 17.

    Cosimbescu, L., Robinson, J.W., Zhou, Y., Qu, J.: Dual functional star polymers for lubricants. RSC Adv. 6, 86259–86268 (2016)

    CAS  Article  Google Scholar 

  18. 18.

    Marx, N., Ponjavic, A., Taylor, R.I., Spikes, H.A.: Study of permanent shear thinning of VM polymer solutions. Tribol. Lett. 65, 106 (2017)

    Article  Google Scholar 

  19. 19.

    Jeong, S.H., Kim, J.M., Baig, C.: Rheological influence of short-chain branching for polymeric materials under shear with variable branch density and branching architecture. Macromolecules 50, 4491–4500 (2017)

    CAS  Article  Google Scholar 

  20. 20.

    Kim, C.A., Kim, J.T., Lee, K., Choi, H.J., Jhon, M.S.: Mechanical degradation of dilute polymer solutions under turbulent flow. Polymer 41, 7611–7615 (2000)

    CAS  Article  Google Scholar 

  21. 21.

    Cosimbescu, L., Robinson, J.W., Page, J.P.: Polymer architecture: does it influence shear stability? Ind. Eng. Chem. Res. 57, 11858–11867 (2018)

    CAS  Article  Google Scholar 

  22. 22.

    Cosimbescu, L., Vellore, A., Ramasamy, U.S., Burgess, S.A., Martini, A.: Low molecular weight polymethacrylates as multi-functional lubricant additives. Eur. Polym. J. 104, 39–44 (2018)

    CAS  Article  Google Scholar 

  23. 23.

    Campbell, K., Erck, R., Swita, M., Cosimbescu, L.: Multifunctional tunable polymethacrylates for enhanced shear stability and wear prevention. ACS Appl. Polym. Mater. 2, 2839–2848 (2020)

    CAS  Article  Google Scholar 

  24. 24.

    Qu, J., Chi, M., Meyer, H.M., Blau, P.J., Dai, S., Luo, H.: Nanostructure and composition of tribo-boundary films formed in ionic liquid lubrication. Tribol. Lett. 43, 205–211 (2011)

    CAS  Article  Google Scholar 

  25. 25.

    Qu, J., Luo, H., Chi, M., Ma, C., Blau, P.J., Dai, S., Viola, M.B.: Comparison of an oil-miscible ionic liquid and ZDDP as a lubricant anti-wear additive. Tribol. Int. 71, 88–97 (2014)

    CAS  Article  Google Scholar 

  26. 26.

    Kohlhauser, B., Ripoll, M.R., Riedl, H., Koller, C.M., Koutna, N., Amsüss, A., Hutter, H., Ramirez, G., Gachot, C., Erdemir, A., Mayrhofer, P.H.: How to get no Wear? A new take on the design of in-situ formed high performing low-friction tribofilms. Mater. Des. 190, 108519 (2020)

    CAS  Article  Google Scholar 

  27. 27.

    Kumara, C., Meyer, H.M., III., Qu, J.: Synergistic interactions between silver and palladium nanoparticles in lubrication. ACS Appl. Nano Mater. 2, 5302–5309 (2019)

    CAS  Article  Google Scholar 

  28. 28.

    Matsui, Y., Aoki, S., Kurosawa, O., Masuko, M.: Concert and blocking effects of polar compounds on the friction reduction and tribofilm formation of zinc dialkyldithiophosphate. Tribol. Online 11, 417–425 (2016)

    Article  Google Scholar 

  29. 29.

    Pereira, G., Lachenwitzer, A., Munoz-Paniagua, D., Kasrai, M., Norton, P.R., Abrecht, M., Gilbert, P.U.: The role of the cation in antiwear films formed from ZDDP on 52100 steel. Tribol. Lett. 23, 109–119 (2006)

    CAS  Article  Google Scholar 

  30. 30.

    Cosimbescu, L., Demas, N.G., Robinson, J.W., Erck, R.A.: Friction-and wear-reducing properties of multifunctional small molecules. ACS Appl. Mater. Interfaces 10, 1317–1323 (2018)

    CAS  Article  Google Scholar 

  31. 31.

    Rigney, D.A., Karthikeyan, S.: The evolution of tribomaterial during sliding: a brief introduction. Tribol. Lett. 39, 3–7 (2010)

    Article  Google Scholar 

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This project was funded by the Office of Vehicle Technology (VTO) of the U.S. Department of Energy (US DOE), (under Contract VT0604000-05450-1004897). PNNL is proudly operated by Battelle for the U.S. DOE (under Contract DE_AC06–76RLO 1830). The authors kindly acknowledge contributions from our colleague Mr. Cortland Johnson (PNNL) for improving the TOC graphic.

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LC proposed the study, analyzed results, and coordinated collaborations. RE conducted friction experiments, analyzes ball and flat surfaces for wear, acquired and analyzed optical images, and interpreted all data. MS and DL acquired SEM and TEM and interpreted data. All authors wrote and reviewed this manuscript.

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Correspondence to Lelia Cosimbescu.

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Erck, R.A., Song, M., Li, D. et al. Investigations of Polymethacrylate Tribochemical Films Using X-Ray Spectroscopy and Optical Profilometry. Tribol Lett 69, 26 (2021).

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  • Organic tribochemical film
  • Polymethacrylates
  • Wear
  • Transmission electron microscopy
  • Scanning electron microscopy
  • Optical imaging