Tribology Letters

, 26:191

Role of nanometer roughness on the adhesion and friction of a rough polymer surface and a molecularly smooth mica surface

  • Bruno Zappone
  • Kenneth J. Rosenberg
  • Jacob Israelachvili
Article

Friction and adhesion measurements between surfaces of cross-linked, stiff polymers of varying roughness against smooth, bare mica surfaces were carried out in dry air as well as in the presence of lubricating oil. The nominal (macroscopic) contact area varies with the applied load according to the Johnson, Kendall and Roberts (JKR) theory, yet shows significant hysteresis due to the irreversibility arising from the loading/unloading curves of multiple asperities. Upon introducing the oil between the surfaces, the critical shear stress is reduced to zero due to the elimination of the adhesion force. However, the effect is less noticeable on the friction coefficient. Lastly, the effect of increasing the (RMS) roughness was greatest over the first few nanometers due to the diminution of the adhesion-controlled contribution to the friction, after which a further increase in roughness had less dramatic effects. A model is presented to account for the observed adhesion hysteresis during repeated loading/unloading cycles of purely elastically deforming rough surfaces.

Keywords

nanotribology contact mechanics surface roughness 

Copyright information

© Springer Science+Business Media, LLC 2006

Authors and Affiliations

  • Bruno Zappone
    • 1
    • 2
  • Kenneth J. Rosenberg
    • 3
  • Jacob Israelachvili
    • 1
  1. 1.Department of Materials and the Materials Research LaboratoryUniversity of CaliforniaSanta BarbaraUSA
  2. 2.Centro di Eccellenza LiCryLUniversity of CalabriaRende (CS)Italy
  3. 3.Department of PhysicsUniversity of CaliforniaSanta BarbaraUSA

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