Atomic force microscope studies of membranes: Force measurement and imaging in electrolyte solutions

W. Richard Bowen, Nidal Hilal, Robert W. Lovitt, Adel O. Sharif, Peter M. Williams

Research output: Contribution to journalArticle


An atomic force microscope has been used to study the electrical double layer interactions between a silicon tip (with an oxidised surface) and two polymeric membranes, one microfiltration (nominally 0.1μm) and the other ultrafiltration (25,000 MWCO), in aqueous NaCl solutions. Force-distance curves were measured for the two membranes at four ionic strengths. The membranes were also imaged under the same conditions using electrical double layer repulsive forces of differing magnitudes - 'electrical double layer mode' imaging. Image analysis was used to determine surface pore size distributions. The force distance curves, together with numerically calculated potential profiles at the entrance to a charged pore, allow an explanation and identification of the optimum imaging conditions. The best images were obtained at high ionic strength with the tip close to the membrane.

Original languageEnglish (US)
Pages (from-to)77-89
Number of pages13
JournalJournal of Membrane Science
Issue number1
StatePublished - Apr 2 1997



  • Atomic force microscopy
  • Electrical double layer
  • Microfiltration
  • Pore size distribution
  • Surface forces
  • Ultrafiltration

ASJC Scopus subject areas

  • Biochemistry
  • Materials Science(all)
  • Physical and Theoretical Chemistry
  • Filtration and Separation

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