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Soft Seminars

Structual superlubricity and curved surfaces

by Astrid de Wijn (NTNY Trondheim)

→ Europe/Stockholm
Albano Building 3

Albano Building 3
Description

Structural superlubricity is a phenomenon where surfaces that are structurally different on the atomic level have extremely low friction. It has been shown in many different combinations of materials in well-controlled lab settings, for example with AFM. Real surfaces, however, are rough, not atomically flat, and this is generally believed to dramatically reduce or destroy the effect.

We have investigated, numerically and analytically, how a the curvature of a contact asperity impacts structural superlubricity [1].  We show that there is no fundamental theoretical reason why a sufficiently gently curved surface could not exhibit structural superlubricity. We investigate this in more detail using molecular-dynamics simulations of a simple contact under nonuniform pressure. We find that the nonuniform distribution of pressure in fact aids superlubricity and reduces friction in general. This opens up possibilities for multi-contact superlubricity in more realistic settings on non-flat surfaces. However, here, wear and coating failure also become important. We also explored how collective effects on patterned surfaces with curved contacts
can lead to damage and destroy superlubricity [2]. I will discuss how the
geometry of surface patterns could be used to improve this [3].


[1] Nonuniform pressure helps structural superlubricity,
Melisa M. Gianetti, Viet Hung Ho, Bjørn Haugen, Graham Cross, Astrid S. de Wijn,
https://arxiv.org/abs/2607.15967
[2] A Theoretical Study on Friction of Macroscale Patterned Surfaces: Implications for Scaling Up Superlubricity,
Viet Hung Ho, Melisa M. Gianetti, Ahmed Uluca, Aaron D. Sinnott, Bjørn Haugen, Graham L. W. Cross, and Astrid S. de Wijn,
ACS Appl. Mater. Interfaces 2025, 17, 40, 56661–56671.
[3] Directional commensurability stabilizes structural superlubricity in patterned mesoscale interfaces,
Viet Hung Ho, Ge Li, Melisa M. Gianetti, Bjørn Haugen, Graham L. W. Cross, Astrid S. de Wijn,
https://arxiv.org/abs/2608.29141