Frictional behaviour of fluororubber against a copper counterface under various loading: insights from MD simulations

Purpose This study aims to explore energy fluctuations during fluororubber–copper friction under varying normal loads using molecular dynamics simulations and elucidates the load-induced mechanisms that govern these fluctuations. Design/methodology/approach A fluororubber model containing 70 Wt.% vinylidene fluoride–hexafluoropropylene was constructed using AutoFF and the OPLS–AA force field and relaxed in LAMMPS via a series of NVT simulations at 298.15 K with a 1 fs time step. A layered fluororubber–copper friction model was then built and further equilibrated. Sliding was simulated at a constant velocity under normal loads of 100, 2,000 and 10,000 MPa for up to 3,000 ps. OVITO was used for post-processing and visualization of molecular structures and temperature fields. Findings Increasing normal load significantly amplifies energy fluctuations in the fluororubber–copper system. Decomposition of the potential energy shows that bond–stretching and bond–angle terms dominate the load-induced energy fluctuations, whereas nonbonded interactions exhibit much smaller variations. Originality/value This work fills a gap in understanding how normal load influences molecular-scale energy dissipation in fluororubber–metal friction. By establishing a direct link between load, conformational changes and the associated bonded energy fluctuations, this study provides valuable insights for the design and optimization of fluororubber components used in high-load tribological environments. Peer review The peer review history for this article is available at: https://publons.com/publon/10.1108/ILT-09-2025-0405