Molar volume and adsorption isotherm dependence of capillary forces in nanoasperity contacts

David B. Asay, Seong Kim

Research output: Contribution to journalArticlepeer-review

42 Scopus citations


The magnitude of the capillary force at any given temperature and adsorbate partial pressure depends primarily on four factors: the surface tension of the adsorbate, its liquid molar volume, its isothermal behavior, and the contact geometry. At large contacting radii, the adsorbate surface tension and the contact geometry are dominating. This is the case of surface force apparatus measurements and atomic force microscopy (AFM) experiments with micrometersize spheres. However, as the size of contacting asperities decreases to the nanoscale as in AFM experiments with sharp tips, the molar volume and isotherm of the adsorbate become very important to capillary formation as well as capillary adhesion. This effect is experimentally and theoretically explored with simple alcohol molecules (ethanol, 1-butanol, and 1-pentanol) which have comparable surface tensions but differing liquid molar volumes. Adsorption isotherms for these alcohols on silicon oxide are also reported.

Original languageEnglish (US)
Pages (from-to)12174-12178
Number of pages5
Issue number24
StatePublished - Nov 20 2007

All Science Journal Classification (ASJC) codes

  • Physical and Theoretical Chemistry
  • Colloid and Surface Chemistry


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