Friction of flat and micropatterned interfaces with nanoscale roughness

Saad Bin Jaber, Alex Hamilton, Yang Xu* (Corresponding Author), Mehmet E. Kartal, Nikolaj Gadegaard, Daniel M Mulvihill* (Corresponding Author)

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

7 Citations (Scopus)
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The dry friction of surfaces with nanoscale roughness and the possibility of using micropatterning to tailor friction by manipulating contact area is investigated. Square wave patterns produced on samples from silicon wafers (and their unstructured equivalent) were slid against unstructured silicon counter surfaces. The width of the square wave features was adjusted to vary the apparent feature contact area. The existence of nanoscale roughness was sufficient to ensure Amontons' first law (F = mu P) on both structured & unstructured samples. Somewhat counterintuitively, friction was independent of the apparent feature contact area making it difficult to tailor friction via the feature contact area. This occurred because, even though the apparent feature contact area was adjusted, the surface roughness and nominal flatness at the contact interface was preserved ensuring that the real contact area and thereby the friction, were likewise preserved. This is an interesting special case, but not universally applicable: friction can indeed be adjusted by structuring provided the intervention leads to a change in real contact area (or interlocking)- and this depends on the specific surface geometry and topography.

Original languageEnglish
Article number106563
Number of pages8
JournalTribology International
Early online date25 Jul 2020
Publication statusPublished - 31 Jan 2021

Bibliographical note

The authors would like to acknowledge the support of the Leverhulme Trust for supporting the work via project grant “Fundamental Mechanical Behaviour of Nano and Micro Structured Interfaces” (RPG-2017-353). EPSRC support (for AH) is also acknowledged via an EPSRC-DTP studentship (EP/N509668/1). We would also like to thank the technical staff at the James Watt Nanofabrication Centre (JWNC) for assistance in fabricating the structured Si samples. The authors also acknowledge the assistance of Ms Sarah Fontana in producing the 3D solid model in Fig. 4. Finally, S.B-J acknowledges the support of the Saudi Arabian Cultural Bureau in London and Al-Imam Mohammad Ibn Saud Islamic University (IMISU), Riyadh for sponsoring and supporting his PhD studies


  • Dry friction
  • Surface structure
  • Surface roughness
  • AREA


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