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Contribution of 1H NMR to the investigation of the adsorption of cationic Gemini surfactants with oligooxyethylene spacer group onto silica
- Source :
- Journal of Colloid and Interface Science, Journal of Colloid and Interface Science, Elsevier, 2009, 331 (2), pp.281-287. ⟨10.1016/j.jcis.2008.12.007⟩
- Publication Year :
- 2009
- Publisher :
- HAL CCSD, 2009.
-
Abstract
- 7 pages; International audience; The present study aims to investigate the behavior of a series of cationic Gemini surfactants with a hydrophilic spacer at liquid–gas and solid–liquid interfaces, with particular emphasis on the effect of spacer length. Gemini surfactants containing two quaternary ammonium groups bound by an ethylene oxide spacer chain, referred to as 12-EOx-12 with x=1,3,7 and 12 were synthesized. Surface tension measurements were used to show that the hydrophilic spacer with oxyethylene moieties was not fully extended at the air–water interface. With increasing the spacer group size, it became sufficiently flexible to adopt a particular conformation with a loop at the water side of the interface. A combined study by adsorption isotherm measurements and 1H NMR spectroscopy allowed a detailed description of the adsorption mechanism of these investigated 12-EOx-12 surfactants, with NMR providing more precise information on the conformation of hydrophilic spacer at the solid–liquid interface. Binding to the silica surface involved one cationic headgroup for the surfactants with a short spacer and the two headgroups for the ones with a long spacer. The number of charged surface sites was estimated by considering the dimeric surfactant as a “molecular ruler.” The small density of adsorption sites gave rise to the formation of pinned surface micelles.
- Subjects :
- Inorganic chemistry
02 engineering and technology
010402 general chemistry
01 natural sciences
Micelle
Biomaterials
Surface tension
chemistry.chemical_compound
Colloid and Surface Chemistry
Adsorption
Pulmonary surfactant
Group (periodic table)
Gemini surfactant
1H NMR spectroscopy
Ethylene oxide
Chemistry
Cationic polymerization
Micellization
[CHIM.MATE]Chemical Sciences/Material chemistry
021001 nanoscience & nanotechnology
0104 chemical sciences
Surfaces, Coatings and Films
Electronic, Optical and Magnetic Materials
Chemical engineering
Proton NMR
Interfacial aggregation
0210 nano-technology
Subjects
Details
- Language :
- English
- ISSN :
- 00219797 and 10957103
- Database :
- OpenAIRE
- Journal :
- Journal of Colloid and Interface Science, Journal of Colloid and Interface Science, Elsevier, 2009, 331 (2), pp.281-287. ⟨10.1016/j.jcis.2008.12.007⟩
- Accession number :
- edsair.doi.dedup.....f4d4ecbf2b9daca204069dd86352db3d