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Measurements of dispersion forces between colloidal latex particles with the atomic force microscope and comparison with Lifshitz theory
- Source :
- Journal of Chemical Physics, Vol. 140, No 104906 (2014)
- Publication Year :
- 2014
- Publisher :
- American Institute of Physics, 2014.
-
Abstract
- Interaction forces between carboxylate colloidal latex particles of about 2 μm in diameter immersed in aqueous solutions of monovalent salts were measured with the colloidal probe technique, which is based on the atomic force microscope. We have systematically varied the ionic strength, the type of salt, and also the surface charge densities of the particles through changes in the solution pH. Based on these measurements, we have accurately measured the dispersion forces acting between the particles and estimated the apparent Hamaker constant to be (2.0 ± 0.5) × 10-21 J at a separation distance of about 10 nm. This value is basically independent of the salt concentration and the type of salt. Good agreement with Lifshitz theory is found when roughness effects are taken into account. The combination of retardation and roughness effects reduces the value of the apparent Hamaker constant and its ionic strength dependence with respect to the case of ideally smooth surfaces. Swiss National Science Foundation CM1101
- Subjects :
- Aqueous solution
carboxylate
Chemistry
Hamaker constant
Analytical chemistry
General Physics and Astronomy
Thermodynamics
London dispersion force
colloidal latex
Colloidal probe technique
Colloid
Ionic strength
ddc:540
Surface roughness
Surface charge
Physical and Theoretical Chemistry
lifshitz theory
Subjects
Details
- Language :
- English
- ISSN :
- 00219606
- Database :
- OpenAIRE
- Journal :
- Journal of Chemical Physics, Vol. 140, No 104906 (2014)
- Accession number :
- edsair.doi.dedup.....aa95a3b416c94b03f3a353b34e36b4f3