PH dependence of friction forces between silica surfaces in solutions

Elena Taran, Bogdan C. Donose, Ivan U. Vakarelski, Ko Higashitani*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

38 Scopus citations


The pH dependence of the friction between a silica particle and a silica wafer was investigated using lateral force microscopy. Measurements were done in the range of 3.6≦pH≦10.6 and the effect of high loading force was also examined. It is found that the friction is independent of the pH of solutions and increases linearly with the applied load, when the pH is between 3.6 and 8.6. On the other hand, once the pH is above 9.0, the friction becomes extremely small and the dependence on the applied load becomes nonlinear. It is postulated that this transition is due to the development of a gel layer composed of polymer-like segments of silicilic acid anchored on the surface; at the lower applied load, this layer acts as a boundary lubricant between the surfaces, but, at the higher applied load, the entanglements of these segments and more direct contact between two solid surfaces leads to the increase of the friction. The effects found here are expected to play an important role in elucidating the basic mechanism of the planarization process of silica wafers.

Original languageEnglish (US)
Pages (from-to)199-203
Number of pages5
JournalJournal of colloid and interface science
Issue number1
StatePublished - May 1 2006
Externally publishedYes


  • CMP
  • Friction
  • Gel layer
  • Silica surface

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Surfaces, Coatings and Films
  • Biomaterials
  • Colloid and Surface Chemistry


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