Measurement of the forces between gold surfaces in water by atomic force microscopy

Simon Biggs, Paul Mulvaney

Research output: Contribution to journalArticle

140 Citations (Scopus)

Abstract

The forces between a flat gold surface and a gold-coated silica sphere have been measured in water using an atomic force microscope. A long-range attractive interaction is observed which is ascribed to the van der Waals interaction between the two surfaces. The force data agree extremely well with recent, calculated values of the Hamaker function (including retardation) for gold/water/gold. The best fit to the experimental data yields a value of 2.5±0.5×10-19 J for the unretarded Hamaker constant. In the presence of cetyltrimethyl ammonium bromide (CTAB) monolayers, electrostatic repulsion is observed at all distances for gold sphere (radius 3.3 μm) interactions with a flat gold surface. However, an attractive force is observed at very small separations for gold-coated silicon nitride tips (effective radius 0.1 μm), which is attributed to penetration of the CTAB monolayers by the sharper tip.

Original languageEnglish
Pages (from-to)8501-8505
Number of pages5
JournalThe Journal of Chemical Physics
Volume100
Issue number11
DOIs
Publication statusPublished - 1 Jan 1994

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Gold
Atomic force microscopy
atomic force microscopy
gold
Water
water
ammonium bromides
Monolayers
radii
interactions
silicon nitrides
Silicon Dioxide
Electrostatics
Microscopes
penetration
microscopes
electrostatics
silicon dioxide

Cite this

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Measurement of the forces between gold surfaces in water by atomic force microscopy. / Biggs, Simon; Mulvaney, Paul.

In: The Journal of Chemical Physics, Vol. 100, No. 11, 01.01.1994, p. 8501-8505.

Research output: Contribution to journalArticle

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