Please use this identifier to cite or link to this item: http://hdl.handle.net/1959.13/27446

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Title
Adsorption of 12-s-12 gemini surfactants at the silica-aqueous solution interface
Author/Creator
Atkin, R.;  Craig, V. S. J.;  Wanless, E. J.;  Biggs, S.
Description
The adsorption of gemini surfactants of the form alkanediyl-α,ω-bis (dodecyldimethylammonium bromide) to a silica substrate is investigated using optical reflectometry (OR) and atomic force microscopy (AFM). The adsorption isotherms and kinetics of adsorption have been determined for spacer sizes of 2, 3, 4, 6, 8, 10, and 12. The maximum surface excess correlates strongly with the size of the spacer group. The smallest spacer size yields the largest surface excess. Soft-contact AFM imaging has shown that flattened ellipsoidal aggregates are present on the surface at the shortest spacer lengths. Images of the adsorbed layer cannot be obtained for spacer sizes greater than 3 because of a strongly attractive force regime. The origin of the attraction is attributed to proximal desorption induced by the approach of the tip toward the substrate. The linear increase in the area per adsorbed molecule with spacer size suggests that the aggregate structures become flattened with increasing spacer size but are otherwise similar.
Relation
Journal of Physical Chemistry Part B: Condensed Matter, Materials, Surfaces, Interfaces & Biophysical Vol. 107, Issue 13, p. 2978-2985
Publisher Link
http://dx.doi.org/10.1021/jp026626o
Date
2003
Publisher
American Chemical Society
Keyword(s)
gemini surfactants;  adsorption;  silica substrate;  dodecyldimethylammonium bromide;  optical reflectometry;  atomic force microscopy
Resource Type
journal article
Identifier
http://hdl.handle.net/1959.13/27446
Identifier
ISSN:1520-6106
Reviewed
Reviewed
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Subject
"Journal of Physical Chemistry Part B: Condensed Matter, Materials, Surfaces, Interfaces & Biophysical"
 
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