Pith. sign in

REVIEW 4 major objections 4 minor 57 references

Strong confinement and steep height gradients in rough lubricated contacts make fluids slide as plugs and cavitate after asperity collisions; a two-fluid immiscible film gives the lowest friction and material transfer.

Reviewed by Pith at T0; open to challenge. T0 means a machine referee read the full paper against a public rubric. the ladder, T0–T4 →

In rough, deformable nanoscale contacts, water, n-dodecane, and their immiscible mixture exhibit plug flow and cavitation; the mixed fluid gives the lowest friction and material transfer.

T0 review reviewed 2026-08-02 challenge →

load-bearing objection A solid, honest NEMD study with a genuinely new rough-contact configuration; the central plug-flow/cavitation mechanism is plausible, but the quasi-1D cell is a real external-validity limit that the authors themselves flag. the 4 major comments →

arxiv 2607.15008 v1 pith:XNZMTYD2 submitted 2026-07-16 cond-mat.soft cond-mat.mes-hallcond-mat.mtrl-sci

Plug Flow and Cavitation in Rough Lubricated Contacts: Molecular Dynamics of Single- vs. Two-Component Fluids

classification cond-mat.soft cond-mat.mes-hallcond-mat.mtrl-sci
keywords molecular dynamicsboundary lubricationmixed lubricationrough contactsplug flowcavitationtwo-fluid lubricantfriction and wear
verification ladder T0 review T1 audit T2 compute T3 formal T4 reserved

The pith

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The reading

Using non-equilibrium molecular dynamics of rough, deformable copper surfaces sliding at 1–50 m/s, the paper tries to show that nanoscale lubrication is governed by intermittent events rather than smooth Couette shear. It reports that strong confinement combined with large height gradients produces plug-like flow—fluid moving almost rigidly with shear concentrated in a sub-nanometre band—and that asperity collisions trigger cavitation, which in water causes abrupt shear-stress release visible beyond the cavity size. Comparing water, n-dodecane, and an immiscible mixture of the two with opposite wall affinities, it finds the mixed lubricant has the lowest friction and least material transfer while keeping plug flow down to the lowest sliding speed. The stakes: if right, favorable two-fluid lubrication previously tied to polymer brushes can be achieved in ordinary rough contacts, and continuum lubrication models need revision at the nanoscale.

Core claim

The paper's central discovery is that the lubrication state in a rough nanoscale contact is not a smooth Couette film but an event-driven competition among three configurations: a pressurized confined film, a cavitated or ruptured film, and direct or near-direct asperity engagement. After asperity collisions, the combination of strong confinement and steep height gradients makes the liquid move as a plug, with slip localized to a layer thinner than about one nanometre, and can nucleate vapor cavities. For water, cavity nucleation releases shear stress abruptly and is tied to sudden drops in normal pressure; for n-dodecane, cavities are more frequent but leave weaker friction signatures becau

What carries the argument

The argument rests on three mechanisms. Plug flow: the confined film translates almost as a rigid block, with shear concentrated in a band thinner than 1 nm, in clear violation of Couette flow. Cavitation: after an asperity collision, tensile hydrodynamic pressure nucleates a bubble that releases normal and shear stress; high-surface-tension liquids like water show sharp signatures, while low-surface-tension n-dodecane nucleates more easily but dissipates over longer times. The mixed-lubricant mechanism: an immiscible water–dodecane interface combined with opposing wall affinities reorganizes the confined film, promotes earlier mechanical accommodation, and suppresses asperity engagement. Th

Load-bearing premise

The load-bearing assumption is that the contact is effectively one-dimensional: the simulation cell is only about 1.8 nm wide with periodic boundaries, so fluid cannot flow around asperities laterally; if a wider cell allowed lateral bypass, plug flow, cavitation, and lip formation could change or disappear.

What would settle it

Run the same rough-contact simulation with the transverse width increased severalfold, or with open lateral boundaries, and check whether the mixed lubricant still shows the lowest friction and material transfer and whether plug flow persists to 1 m/s; if plug flow and lip formation vanish or the ranking reverses, the central claims are geometry-specific rather than general.

Watch this falsifier. Get emailed when new claim-graph text bears on it.

If this is right

  • Continuum Reynolds- or slip-length-based descriptions are not valid for rough contacts at nanometre separations; flow is plug-like with a localized shear zone below 1 nm.
  • Cavitation after asperity collisions is a nanoscale stress-release pathway that should be included in mixed-lubrication models rather than treated as a rare artifact.
  • The immiscible two-fluid concept can transfer from polymer-brush systems to brush-free rough contacts, giving lower friction and reduced material transfer at low to moderate speeds.
  • Friction coefficient and surface protection are decoupled: similar friction coefficients can accompany very different amounts of asperity contact, so wear and friction need separate predictions.
  • At high sliding speeds the mixed lubricant can generate folding lips that detach as transient wear particles, implying speed-dependent wear mechanisms beyond simple Archard scaling.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • If plug flow persists in wider cells, nanoscale friction may be understood as a stochastic sequence of film-rupture events, with sliding speed setting event frequency rather than viscous shear rate; this would change how Stribeck-like curves are interpreted.
  • Opposing wall affinities may be a design principle for water-based lubricants: modest chemical patterning of surfaces could stabilize a water-rich/oil-rich bilayer and cut wear without polymer brushes.
  • The quasi-one-dimensional cell may suppress lateral cavitation jets and fluid bypass; a wider cell could alter cavity lifetimes and make lip detachment rarer, so the ranking should be re-tested in three-dimensional rough contacts.
  • The pressure-matched results suggest water's poor boundary protection stems from film instability rather than low viscosity, pointing to additives that strengthen water films as a cheaper route to aqueous lubrication.
Share X Bluesky LinkedIn Reddit HN

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit.

Referee Report

4 major / 4 minor

Summary. The paper reports non-equilibrium molecular dynamics simulations of water, n-dodecane, and an immiscible water/dodecane mixture lubricating rough, deformable copper surfaces under mixed/boundary-lubrication conditions. The authors use a long sliding direction with quasi-incommensurate, rough walls and a thin transverse cell. The central claims are: (i) strong confinement plus large height gradients produce non-Couette plug flow and cavitation triggered by asperity collisions; (ii) water shows stronger speed dependence but reduced load-bearing capacity compared with dodecane despite similar ambient viscosities; (iii) the mixed lubricant maintains plug flow to the lowest sliding velocity and exhibits the lowest friction and material transfer; and (iv) only the mixed system develops folding lips and, at high speed, transient wear particles. A spring-based boundary condition is introduced to interpolate between fixed-displacement and fixed-load control, and a pressure-matched comparison is attempted by tuning the spring stiffness.

Significance. If the findings are robust, they constitute a useful step beyond smooth-interface and single-asperity MD lubrication studies, identifying event-driven, non-Couette flow as a distinct mechanism in rough nanoscale contacts and suggesting that an immiscible two-fluid film can provide benefits without polymer brushes. The simulation protocol is standard and reasonably described: EAM copper, TIP4P water, OPLS-AA dodecane, quasi-incommensurate surfaces, multiple sliding velocities, and time-resolved stress/flow diagnostics. The paper does not fit parameters to its conclusions. However, the generality of the central mechanism and the mixed-lubricant ranking is currently conditional on a quasi-1D geometry and on a single roughness realization with no error bars. The significance is therefore real but not yet demonstrated at the level claimed in the abstract.

major comments (4)
  1. [§2.1.1 and Conclusion] The simulation cell is only Ly ≈ 17.8 Å wide, with roughness h(x) independent of y and periodic boundary conditions, so the system is effectively two-dimensional and fluid cannot flow around asperities laterally. The Conclusion explicitly acknowledges that a larger transverse size with roughness would allow lateral bypass. This is load-bearing because the central claims—plug-flow persistence, cavitation after asperity collisions, and the mixed lubricant's advantage in maintaining plug flow to low speeds—could be artifacts of the imposed no-bypass geometry. I request at least one wider-cell (e.g., Ly ≈ 50–100 Å) and/or a 3D roughness realization at 10 and 50 m/s, or the abstract and conclusions must be substantially tempered to present the results as a quasi-2D proof of concept.
  2. [§3.4 and Abstract] The abstract states that the mixed lubricant exhibits 'the lowest friction and material transfer,' but the quantitative support is weaker. In §3.4 the normalized transfer counts at ~100 nm are 0.14/0.18 atoms/MPa for the mixed case versus 0.17/0.17 for n-dodecane at 50/10 m/s, and the text explicitly says the mixed fluid provides only 'a small overall wear reduction compared to n-dodecane.' Similarly, §3.5 reports mixed friction as 'similar' to dodecane, with a reduction only at the smallest speed. The abstract's ranking is therefore overstated. Please provide a statistical comparison across independent runs or revise the claims to match the actual magnitudes.
  3. [§3.5, Fig. 8 and §3.4] All quantitative comparisons rest on a single trajectory per condition and a single roughness realization, with no error bars or repeat simulations. Friction-difference claims such as water rising from 0.23 at 1 m/s to 0.31 at 10 m/s, and the mixed lubricant being 'lowest,' are not testable against noise. The same issue affects wear counts, which are small and fluctuate non-monotonically. Because the mixed-lubricant ranking is a central conclusion, this is a load-bearing sampling problem. Multiple independent seeds/realizations and standard deviations (or at least representative ranges) are needed before quantitative ranking claims can be made.
  4. [§3.6] The pressure-matched comparison is achieved by adjusting the spring stiffness k for dodecane and the mixed fluid so that ⟨pzz⟩ approximately matches water. Since k controls the wall compliance and therefore the entire boundary condition, this is not a clean one-variable pressure match: it also changes the mechanical response of the solids. This does not invalidate the qualitative morphology discussion, but the friction-coefficient comparison in Fig. 9 should be interpreted with this coupling in mind and the residual confound should be discussed explicitly.
minor comments (4)
  1. [§2.2] The formula for the spring stiffness as printed appears dimensionally inconsistent: it should read k = πE*ΔA / sqrt(2πΔhLx) (missing division sign), which yields the quoted value k ≈ 0.35 N/m with the stated parameters.
  2. [Data Availability] The statement 'The manuscript does not report data generation' is confusing for an MD study. Please deposit input files, force-field parameters, and post-processing codes in a public repository, or at least clarify what is absent.
  3. [Throughout] Several typos and inconsistencies need correction, e.g., 'n−doedecane' (§3.5), 'futher' (Conclusion), 'extnet' (§3.2), and inconsistent use of 'vM' vs 'von Mises'.
  4. [§3.1] Cavitation is inferred from visual inspection of snapshots and pressure drops. For a quantitative claim about cavitation frequency and size, an objective void-detection algorithm (e.g., local density or Voronoi volume analysis) with time series would strengthen the paper.

Circularity Check

0 steps flagged

No significant circularity: the central claims are simulation outputs, not fitted inputs or self-cited derivations; author-overlap citations are motivational context only.

full rationale

The paper's load-bearing claims—plug flow, cavitation after asperity collisions, and the mixed-lubricant ranking—are direct outputs of non-equilibrium MD simulations. The simulation inputs are interatomic potentials, roughness geometry, boundary conditions, and an imposed sliding protocol (Sections 2.1–2.3); none of these are defined in terms of the target results. The spring stiffness k is derived from a stated elastic half-space estimate, k=πE*ΔA/√(2πΔhLx), and is not fitted to friction or wear outcomes. The pressure-matched comparison of Section 3.6 is an experimental control, not a circular reconstruction: it changes the boundary stiffness to bring ⟨pzz⟩ into agreement and then compares the resulting friction and contact morphology. The only author-overlap citations ([34,35] used to motivate the mixed brush-lubrication question) provide context rather than evidence for the present simulation results; the paper explicitly tests whether such brush behavior 'can also be realized in rough contacts without brushes' and does not use those papers' parameters or conclusions as inputs. The acknowledged limitation regarding transverse system size (Conclusion: 'A larger transverse-size along with the roughness would allow fluid domain to laterally bypass the asperity obstacles') is an external-validity caveat, not a sign that the derived quantities are built into the model. No fitted parameter is renamed as a prediction, no uniqueness theorem is imported from prior self-cited work, and no known result is merely relabeled. The paper is self-contained against its own data generation; the derivation chain is not circular.

Axiom & Free-Parameter Ledger

5 free parameters · 5 axioms · 0 invented entities

No new particles, forces, or conserved quantities are introduced. The free parameters are standard MD modeling choices plus the specific roughness and wetting parameters; the strongest load-bearing assumptions are force-field transferability, the semi-infinite spring boundary approximation, and the adequacy of the very narrow transverse cell.

free parameters (5)
  • spring stiffness k = ≈0.35 N/m
    Chosen to approximate half-space stiffness via geometric mean over the wavelength range; controls load fluctuations and pressure response, and is tuned for the matched-pressure comparison.
  • wall-fluid LJ epsilon scaling (mixed system) = 2× for wetting pairs, 0.5× for complementary pairs
    Imposed to create preferential wetting of the top wall by water and the bottom wall by dodecane; directly determines phase separation and mixed-lubricant behavior.
  • water-dodecane cross-interaction scaling = εij=1.07√εiεj, σij=0.85(σi+σj)/2
    Adopted from Krämer et al. to suppress spurious water-alkane mixing; affects the liquid-liquid interface, cavitation, and the friction/morphology results.
  • roughness spectrum parameters = H=0.8, q_r=4q_0, z0=5a0, nmax=Lx/(2a0)-1, clip at -a0/2
    Define the single self-affine topography used in all simulations; only one realization is studied, so statistical robustness of the observed mechanisms is unknown.
  • maximum initial penetration = ≈2.7 Å
    Sets the initial load and confinement; comparisons across lubricants depend on this chosen condition.
axioms (5)
  • domain assumption EAM copper, TIP4P water, and OPLS-AA dodecane force fields are transferable to GPa pressures, 1–50 m/s shear, and plastic asperity contact
    Section 2.3; all material-transfer, cavitation, and stress-release claims rely on these potentials.
  • domain assumption Harmonic spring coupling of outer layers with k≈0.35 N/m approximates a semi-infinite elastic wall; the factor-1.63 over-stiffness of the longest mode is acceptable
    Section 2.2; friction and stress fluctuations depend on this boundary condition.
  • domain assumption Modified Lorentz-Berthelot cross interactions suppress water-dodecane mixing while preserving a realistic interfacial tension
    Section 2.3; mixed-lubricant phase separation and fluid-fluid interface observations depend on this.
  • domain assumption The thin quasi-1D cell (Ly≈17.8 Å) with periodic boundaries captures the essential asperity-interaction physics
    Section 2.1.1 and conclusion; the authors acknowledge that lateral bypass is absent and may change the results.
  • domain assumption Thermostat acting only in the y-direction leaves x-direction flow and stress release physically unaffected
    Section 2.4; needed to interpret friction force and localized temperature fields.

reviewed 2026-08-02 · how reviews work

0 comments
Cite this review

Pith. "Pith review of Plug Flow and Cavitation in Rough Lubricated Contacts: Molecular Dynamics of Single- vs. Two-Component Fluids." pith.science (2026). https://pith.science/paper/XNZMTYD2

@misc{pith2026260715008,
  author       = {Pith},
  title        = {Pith review of: Plug Flow and Cavitation in Rough Lubricated Contacts: Molecular Dynamics of Single- vs. Two-Component Fluids},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/XNZMTYD2}},
  note         = {Machine review of arXiv:2607.15008}
}
Share X Bluesky LinkedIn Reddit HN
abstract

We present non-equilibrium molecular dynamics simulations of lubricated sliding between rough, deformable surfaces under conditions representative of boundary and mixed lubrication. One aim is to reduce the gap between highly idealized simulations of smooth interfaces and real, rough, load-bearing contacts. Another aim is to determine whether favorable tribological properties of two-fluid lubrication reported for solvated hydrophilic-hydrophobic polymer-brush interfaces can also be realized in rough contacts without brushes. To this end, we compare aqueous (water), hydrocarbon ($n$-dodecane), which has a similar equilibrium viscosity to water at ambient conditions, and immiscible two-fluid lubrication under identical geometric conditions. For the single-component lubricants, the simulations reproduce established trends: Water shows stronger speed dependence but reduced load-bearing capacity than $n$-dodecane, despite their similar ambient viscosities. Beyond this expected behavior, the simulations reveal that the combination of strong confinement and large height gradients can cause plug flow and cavitation after asperity collisions. For a high-surface-tension liquid like water, cavitation provides a mechanism for abrupt shear-stress release observable on scales much exceeding the size of the cavity. The mixed lubricant exhibits the lowest friction and material transfer, while maintaining plug flow to the lowest sliding velocity. It is also the only system in which folding lips form, occasionally developing into transient wear particles at high speeds.

Figures

Figures reproduced from arXiv: 2607.15008 by Martin H. M\"user, Shubham Agarwal.

Figure 1
Figure 1. Figure 1: Residual stresses in the simulation blocks after equilibration [PITH_FULL_IMAGE:figures/full_fig_p006_1.png] view at source ↗
Figure 2
Figure 2. Figure 2: A schematic showing the spring setup used in the present simulations. The atoms [PITH_FULL_IMAGE:figures/full_fig_p007_2.png] view at source ↗
Figure 3
Figure 3. Figure 3: Water-lubricated contact at three sliding velocities. (a) Mean normal pressure [PITH_FULL_IMAGE:figures/full_fig_p011_3.png] view at source ↗
Figure 4
Figure 4. Figure 4: n-Dodecane-lubricated contact at three sliding velocities. (a) Mean normal pressure pzz and (b) shear stress τ vs. slid-distance dslid. Mean values are given in parentheses in the legend. Configurational snapshots at four slid-distances are shown for (c) 50 m/s, (d) 10 m/s, and (e) 1 m/s. The corresponding slid-distance (dslid) is mentioned at the left. The copper blocks are colored by the von-Mises stress… view at source ↗
Figure 4
Figure 4. Figure 4: One distinguishing feature is that the friction at the smallest velocity [PITH_FULL_IMAGE:figures/full_fig_p016_4.png] view at source ↗
Figure 5
Figure 5. Figure 5: Interface evolution for mixed lubricated contact. Water is represented in blue [PITH_FULL_IMAGE:figures/full_fig_p017_5.png] view at source ↗
Figure 6
Figure 6. Figure 6: Mixed-lubricated contact at three sliding velocities. (a) Mean normal pressure [PITH_FULL_IMAGE:figures/full_fig_p018_6.png] view at source ↗
Figure 7
Figure 7. Figure 7: Number of atoms transferred from one wall to the other as a function of sliding [PITH_FULL_IMAGE:figures/full_fig_p019_7.png] view at source ↗
Figure 8
Figure 8. Figure 8: Effect of lubricant and sliding speed on friction coefficient. [PITH_FULL_IMAGE:figures/full_fig_p020_8.png] view at source ↗
Figure 9
Figure 9. Figure 9: Effect of lubricant at roughly matched normal pressure and sliding speed of [PITH_FULL_IMAGE:figures/full_fig_p021_9.png] view at source ↗
Figure 10
Figure 10. Figure 10: Local temperature maps for solid and fluid (water) phase during (left) asperity [PITH_FULL_IMAGE:figures/full_fig_p022_10.png] view at source ↗

discussion (0)

Sign in with ORCID, Apple, or X to comment. Anyone can read and Pith papers without signing in.

Reference graph

Works this paper leans on

57 extracted references · 15 canonical work pages

  1. [1]

    F. P. Bowden, D. Tabor, The friction and lubrication of solids, Oxford University Press, New York, 1950

  2. [2]

    B. N. Persson, Theory of rubber friction and contact mechanics, The Journal of Chemical Physics 115 (8) (2001) 3840–3861

  3. [3]

    B. N. J. Persson, Functional properties of rough surfaces from an an- alytical theory of mechanical contact, MRS Bulletin 47 (12) (2022) 1211–1219.doi:10.1557/s43577-022-00472-6. URLhttp://dx.doi.org/10.1557/s43577-022-00472-6 24

  4. [4]

    M. H. Müser, W. B. Dapp, R. Bugnicourt, P. Sainsot, N. Lesaffre, T. A. Lubrecht, B. N. Persson, K. Harris, A. Bennett, K. Schulze, et al., Meet- ingthecontact-mechanicschallenge, TribologyLetters65(4)(2017)118

  5. [5]

    W. B. Dapp, A. Lücke, B. N. Persson, M. H. Müser, Self-affine elas- tic contacts: percolation and leakage, Physical review letters 108 (24) (2012) 244301

  6. [6]

    Scaraggi, G

    M. Scaraggi, G. Carbone, B. N. J. Persson, D. Dini, Lubrication in soft rough contacts: A novel homogenized approach. part i - theory, Soft Matter 7 (21) (2011) 10395.doi:10.1039/c1sm05128h. URLhttp://dx.doi.org/10.1039/C1SM05128H

  7. [7]

    Paggi, A

    M. Paggi, A. Amicarelli, P. Lenarda, Sph modelling of hydrodynamic lubrication along rough surfaces, Lubricants 7 (12) (2019) 103.doi: 10.3390/lubricants7120103. URLhttp://dx.doi.org/10.3390/lubricants7120103

  8. [8]

    Putignano, L

    C. Putignano, L. Afferrante, G. Carbone, G. Demelio, A new efficient numerical method for contact mechanics of rough surfaces, International Journal of Solids and Structures 49 (2) (2012) 338–343.doi:10.1016/ j.ijsolstr.2011.10.009. URLhttp://dx.doi.org/10.1016/j.ijsolstr.2011.10.009

  9. [9]

    Putignano, G

    C. Putignano, G. Carbone, D. Dini, Mechanics of rough contacts in elastic and viscoelastic thin layers, International Journal of Solids and Structures 69-70 (2015) 507–517.doi:10.1016/j.ijsolstr.2015.04. 034. URLhttp://dx.doi.org/10.1016/j.ijsolstr.2015.04.034

  10. [10]

    Q. Wang, S. Ardah, T. Reddyhoff, D. Dini, Multiscale fluid–structure interactions in compliant lubricated interfaces, International Journal of Engineering Science 227 (2026) 104619.doi:10.1016/j.ijengsci. 2026.104619. URLhttp://dx.doi.org/10.1016/j.ijengsci.2026.104619

  11. [11]

    R. G. Horn, J. N. Israelachvili, Direct measurement of structural forces between two surfaces in a nonpolar liquid, The Journal of Chemical Physics 75 (3) (1981) 1400–1411.doi:10.1063/1.442146. URLhttp://dx.doi.org/10.1063/1.442146 25

  12. [12]

    S. T. Cui, P. T. Cummings, H. D. Cochran, Molecular simulation of the transition from liquidlike to solidlike behavior in complex fluids confined to nanoscale gaps, The Journal of Chemical Physics 114 (16) (2001) 7189–7195.doi:10.1063/1.1359736. URLhttp://dx.doi.org/10.1063/1.1359736

  13. [13]

    H. Gao, M. H. Müser, Why liquids can appear to solidify during squeeze- out – even when they don’t, Journal of Colloid and Interface Science 562 (2020) 273–278.doi:10.1016/j.jcis.2019.10.097. URLhttp://dx.doi.org/10.1016/j.jcis.2019.10.097

  14. [14]

    URLhttp://dx.doi.org/10.1039/b616490k

    L.Bocquet, J.-L.Barrat, Flowboundaryconditionsfromnano-tomicro- scales, Soft Matter 3 (6) (2007) 685.doi:10.1039/b616490k. URLhttp://dx.doi.org/10.1039/b616490k

  15. [15]

    L.-T. Kong, C. Denniston, M. H. Müser, The crucial role of chemi- cal detail for slip-boundary conditions: molecular dynamics simulations of linear oligomers between sliding aluminum surfaces, Modelling and Simulation in Materials Science and Engineering 18 (3) (2010) 034004. doi:10.1088/0965-0393/18/3/034004. URLhttp://dx.doi.org/10.1088/0965-0393/18/3/034004

  16. [16]

    Holey, P

    H. Holey, P. Gumbsch, L. Pastewka, Active learning for nonparametric multiscale modeling of boundary lubrication, Science Advances 11 (37) (2025).doi:10.1126/sciadv.adx4546. URLhttp://dx.doi.org/10.1126/sciadv.adx4546

  17. [17]

    P. M. Lugt, G. E. Morales-Espejel, A review of elasto-hydrodynamic lubrication theory, Tribology Transactions 54 (3) (2011) 470–496

  18. [18]

    J. P. Ewen, H. A. Spikes, D. Dini, Contributions of molecular dynamics simulations to elastohydrodynamic lubrication, Tribology Letters 69 (1) (2021) 24

  19. [19]

    J. P. Ewen, D. Heyes, D. Dini, Advances in nonequilibrium molecular dynamics simulations of lubricants and additives, Friction 6 (4) (2018) 349–386

  20. [20]

    Spikes, Mixed lubrication—an overview, Lubrication Science 9 (3) (1997) 221–253

    H. Spikes, Mixed lubrication—an overview, Lubrication Science 9 (3) (1997) 221–253. 26

  21. [21]

    Stephan, S

    S. Stephan, S. Schmitt, H. Hasse, H. M. Urbassek, Molecular dynamics simulation of the Stribeck curve: Boundary lubrication, mixed lubri- cation, and hydrodynamic lubrication on the atomistic level, Friction 11 (12) (2023) 2342–2366

  22. [22]

    Savio, L

    D. Savio, L. Pastewka, P. Gumbsch, Boundary lubrication of heteroge- neous surfaces and the onset of cavitation in frictional contacts, Science Advances 2 (3) (2016) e1501585

  23. [23]

    S. Eder, A. Vernes, G. Vorlaufer, G. Betz, Molecular dynamics simula- tions of mixed lubrication with smooth particle post-processing, Journal of Physics: Condensed Matter 23 (17) (2011) 175004

  24. [24]

    Pastewka, A

    L. Pastewka, A. I. Vakis, S. J. Eder, R. Aghababaei, A. Almqvist, G. Carbone, M. Chandross, D. Dini, H. J. Ehrich, J. P. Ewen, N. Menga, J.-F. Molinari, G. Moras, L. Nicola, M. Paggi, C. Putignano, M. Scaraggi, V. A. Yastrebov, M. H. Müser, Modeling in tribology: Re- cent advances, applications, and open questions, Tribology International 218 (2026) 11132...

  25. [25]

    Motezaker, S

    M. Motezaker, S. Xiao, A. R. Khoei, J. A. Zakeri, Molecular dynamics insights into nanoscale lubrication: a comparative study of regimes, Ap- plied Physics A 130 (8) (2024).doi:10.1007/s00339-024-07712-3. URLhttp://dx.doi.org/10.1007/s00339-024-07712-3

  26. [26]

    M. H. Müser, Nature of mechanical instabilities and their effect on ki- netic friction, Physical Review Letters 89 (22) (2002).doi:10.1103/ physrevlett.89.224301. URLhttp://dx.doi.org/10.1103/PhysRevLett.89.224301

  27. [27]

    S. E. Restrepo, M. C. van Eijk, J. P. Ewen, Behaviour of n-alkanes confined between iron oxide surfaces at high pressure and shear rate: A nonequilibrium molecular dynamics study, Tribology International 137 (2019) 420–432

  28. [28]

    Mehrnia, P

    S. Mehrnia, P. F. Pelz, Tribological design by molecular dynamics simu- lation: Influence of the molecular structure on wall slip and bulk shear, Chemical Engineering & Technology 46 (1) (2023) 95–101. 27

  29. [29]

    Barsky, M

    S. Barsky, M. O. Robbins, Molecular dynamics study of slip at the interface between immiscible polymers, Physical Review E 63 (2) (2001) 021801

  30. [30]

    L.-T. Kong, C. Denniston, M. H. Müser, Y. Qi, Non-bonded force field for the interaction between metals and organic molecules: a case study of olefins on aluminum, Physical Chemistry Chemical Physics 11 (43) (2009) 10195–10203

  31. [31]

    H. Yao, H. Spikes, C. Matta, F. Berens, A. Kadiric, Surface fatigue behaviour of water-based lubricants, Tribology International (2026) 112214

  32. [32]

    K. Falk, F. Sedlmeier, L. Joly, R. R. Netz, L. Bocquet, Molecular origin of fast water transport in carbon nanotube membranes: Superlubric- ity versus curvature dependent friction, Nano Letters 10 (10) (2010) 4067–4073.doi:10.1021/nl1021046. URLhttp://dx.doi.org/10.1021/nl1021046

  33. [33]

    J. S. Bhamra, E. M. Everhard, J. A. Bomidi, D. Dini, J. P. Ewen, Comparing the tribological performance of water-based and oil-based drilling fluids in diamond–rock contacts, Tribology Letters 72 (1) (2024) 19

  34. [34]

    De Beer, E

    S. De Beer, E. Kutnyanszky, P. M. Schön, G. J. Vancso, M. H. Müser, Solvent-induced immiscibility of polymer brushes eliminates dissipation channels, Nature communications 5 (1) (2014) 3781

  35. [35]

    de Beer, M

    S. de Beer, M. H. Müser, Friction in (im-) miscible polymer brush sys- tems and the role of transverse polymer tilting, Macromolecules 47 (21) (2014) 7666–7673.doi:10.1021/ma501718b. URLhttp://dx.doi.org/10.1021/ma501718b

  36. [36]

    J. Bian, L. Nicola, On the lubrication of rough copper surfaces with graphene, Tribology International 156 (2021) 106837.doi:10.1016/j. triboint.2020.106837. URLhttp://dx.doi.org/10.1016/j.triboint.2020.106837

  37. [37]

    M. H. Müser, S. V. Sukhomlinov, L. Pastewka, Interatomic potentials: achievements and challenges, Advances in Physics: X 8 (1) (Nov. 2022). 28 doi:10.1080/23746149.2022.2093129. URLhttp://dx.doi.org/10.1080/23746149.2022.2093129

  38. [38]

    Mishin, M

    Y. Mishin, M. J. Mehl, D. A. Papaconstantopoulos, A. F. Voter, J. D. Kress, Structural stability and lattice defects in copper: Ab initio, tight- binding, and embedded-atom calculations, Physical Review B 63 (22) (2001) 224106

  39. [39]

    Gravelle, C

    S. Gravelle, C. M. Alvares, J. R. Gissinger, A. Kohlmeyer, A set of tu- torials for the lammps simulation package [article v1. 0], Living Journal of Computational Molecular Science 6 (1) (2025) 3027–3027

  40. [40]

    H.Zhang, L.Pan, X.Xie, Moleculardynamicssimulationonbehaviorsof water nanodroplets impinging on moving surfaces, Nanomaterials 12 (2) (2022) 247

  41. [41]

    Heinz, R

    H. Heinz, R. Vaia, B. Farmer, R. Naik, Accurate simulation of surfaces and interfaces of face-centered cubic metals using 12- 6 and 9- 6 lennard- jones potentials, The Journal of Physical Chemistry C 112 (44) (2008) 17281–17290

  42. [42]

    W. L. Jorgensen, D. S. Maxwell, J. Tirado-Rives, Development and testing of the opls all-atom force field on conformational energetics and properties of organic liquids, Journal of the American Chemical Society 118 (45) (1996) 11225–11236

  43. [43]

    Krämer, F

    A. Krämer, F. C. Pickard IV, J. Huang, R. M. Venable, A. C. Simmon- ett, D. Reith, K. N. Kirschner, R. W. Pastor, B. R. Brooks, Interactions of water and alkanes: Modifying additive force fields to account for po- larization effects, Journal of Chemical Theory and Computation 15 (6) (2019) 3854–3867

  44. [44]

    Grønbech-Jensen, O

    N. Grønbech-Jensen, O. Farago, A simple and effective verlet-type al- gorithm for simulating langevin dynamics, Molecular Physics 111 (8) (2013) 983–991.doi:10.1080/00268976.2012.760055. URLhttp://dx.doi.org/10.1080/00268976.2012.760055

  45. [45]

    Grønbech-Jensen, Complete set of stochastic verlet-type thermostats for correct langevin simulations, Molecular Physics 118 (8) (2019) e1662506.doi:10.1080/00268976.2019.1662506

    N. Grønbech-Jensen, Complete set of stochastic verlet-type thermostats for correct langevin simulations, Molecular Physics 118 (8) (2019) e1662506.doi:10.1080/00268976.2019.1662506. URLhttp://dx.doi.org/10.1080/00268976.2019.1662506 29

  46. [46]

    A. P. Thompson, H. M. Aktulga, R. Berger, D. S. Bolintineanu, W. M. Brown, P. S. Crozier, P. J. in ’t Veld, A. Kohlmeyer, S. G. Moore, T. D. Nguyen, R. Shan, M. J. Stevens, J. Tranchida, C. Trott, S. J. Plimpton, Lammps-aflexiblesimulationtoolforparticle-basedmaterialsmodeling at the atomic, meso, and continuum scales, Computer Physics Commu- nications 27...

  47. [47]

    Scherge, D

    M. Scherge, D. Linsler, T. Schlarb, The running-in corridor of lubricated metal–metal contacts, Wear 342 (2015) 60–64

  48. [48]

    Baskar, G

    S. Baskar, G. Sriram, Tribological behavior of journal bearing material under different lubricants., Tribology in Industry 36 (2) (2014)

  49. [49]

    Rameshkumar, I

    T. Rameshkumar, I. Rajendran, A. Latha, Investigation on the mechan- ical and tribological properties of aluminium-tin based plain bearing material, Tribology in Industry 32 (2) (2010) 3

  50. [50]

    H. Liu, B. Zhang, N. Bader, C. Venner, G. Poll, Simplified traction prediction for highly loaded rolling/sliding ehl contacts, Tribology In- ternational 148 (2020) 106335

  51. [51]

    Wang, Y.-B

    Y.-L. Wang, Y.-B. Zhang, X. Cui, X.-L. Liang, R.-Z. Li, R.-X. Wang, S. Sharma, M.-Z. Liu, T. Gao, Z.-M. Zhou, et al., High-speed grinding: from mechanism to machine tool, Advances in Manufacturing 13 (1) (2025) 105–154

  52. [52]

    S. S. Brenner, Tensile strength of whiskers, Journal of Applied Physics 27 (12) (1956) 1484–1491.doi:10.1063/1.1722294. URLhttp://dx.doi.org/10.1063/1.1722294

  53. [53]

    Roundy, C

    D. Roundy, C. R. Krenn, M. L. Cohen, J. W. Morris, Ideal shear strengths of fcc aluminum and copper, Physical Review Letters 82 (13) (1999) 2713–2716.doi:10.1103/physrevlett.82.2713. URLhttp://dx.doi.org/10.1103/PhysRevLett.82.2713

  54. [54]

    Reye, Zur theorie der zapfenreibung, Der Civilingenieur

    T. Reye, Zur theorie der zapfenreibung, Der Civilingenieur. Neue Folge 6 (1860) 235–255

  55. [55]

    J. F. Archard, Contact and rubbing of flat surfaces, J. Appl. Phys. 24 (1953) 981.doi:10.1063/1.1721448. 30

  56. [56]

    J. L. Bentley, Multidimensional binary search trees used for associative searching, Communications of the ACM 18 (9) (1975) 509–517

  57. [57]

    M. H. Müser, B. N. J. Persson, On the flash temperature in sliding con- tacts (2026).arXiv:2603.29547,doi:10.48550/arXiv.2603.29547. 31 Appendix A. Material for Supplementary Material Section Appendix A.1. Rotated elastic tensor Starting from the cubic stiffness tensor C=   C11 C12 C12 0 0 0 C12 C11 C12 0 0 0 C12 C12 C11 0 0 0 0 0 0C 44 0 0 0 0 0 ...

This paper was first reviewed by deepseek-v4-flash on August 2, 2026.