Amine functionalized surfactants — pH effects on adsorption and interaction

Claesson, Per M.; Herder, P. C. Den; Rutland, Mark W.; Waltermo, Aasa; Anhede, B.

doi:10.1007/bfb0114419

Cited by 12 publications

(9 citation statements)

References 28 publications

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“…At pH 8, monotonically repulsive forces of a double-layer repulsion-type are observed which correspond to apparent surface potentials of -60 and -40 mV for the probe and film, respectively. While somewhat surprising that the amine probe is negatively charged, these findings concur with previous work showing that amine SAMs 75,76 and adsorbed amine-functionalized surfactants 77,78 are negatively charged when subjected to pH conditions well above their pK a . Moreover, the exact pK a for this SAM system is unknown since the acid-base equilibrium shifts when chemical species are adsorbed on a surface and the characterization of such functionalized colloidal particles is limited.…”

Section: Atomic Force Microscopy Imaging (Afm) An Mfp-3dsupporting

confidence: 88%

Direct Surface Force Measurements of Polyelectrolyte Multilayer Films Containing Nanocrystalline Cellulose

2010

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Polyelectrolyte multilayer films containing nanocrystalline cellulose (NCC) and poly(allylamine hydrochloride) (PAH) make up a new class of nanostructured composite with applications ranging from coatings to biomedical devices. Moreover, these materials are amenable to surface force studies using colloid-probe atomic force microscopy (CP-AFM). For electrostatically assembled films with either NCC or PAH as the outermost layer, surface morphology was investigated by AFM and wettability was examined by contact angle measurements. By varying the surrounding ionic strength and pH, the relative contributions from electrostatic, van der Waals, steric, and polymer bridging interactions were evaluated. The ionic cross-linking in these films rendered them stable under all solution conditions studied although swelling at low pH and high ionic strength was inferred. The underlying polymer layer in the multilayered film was found to dictate the dominant surface forces when polymer migration and chain extension were facilitated. The precontact normal forces between a silica probe and an NCC-capped multilayer film were monotonically repulsive at pH values where the material surfaces were similarly and fully charged. In contrast, at pH 3.5, the anionic surfaces were weakly charged but the underlying layer of cationic PAH was fully charged and attractive forces dominated due to polymer bridging from extended PAH chains. The interaction with an anionic carboxylic acid probe showed similar behavior to the silica probe; however, for a cationic amine probe with an anionic NCC-capped film, electrostatic double-layer attraction at low pH, and electrostatic double-layer repulsion at high pH, were observed. Finally, the effect of the capping layer was studied with an anionic probe, which indicated that NCC-capped films exhibited purely repulsive forces which were larger in magnitude than the combination of electrostatic double-layer attraction and steric repulsion, measured for PAH-capped films. Wherever possible, DLVO theory was used to fit the measured surface forces and apparent surface potentials and surface charge densities were calculated.

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Section: Atomic Force Microscopy Imaging (Afm) An Mfp-3dsupporting

confidence: 88%

Direct Surface Force Measurements of Polyelectrolyte Multilayer Films Containing Nanocrystalline Cellulose

2010

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“…The mica basal plane can be regarded as a hydrophilic oxide surface in aqueous electrolyte solutions and the mica basal plane−cationic surfactant system has been utilized in a number of surface force apparatus investigations. Most of the surface force work was directed at understanding the long-range attractive interaction between surfactant coated surfaces. − The latter area of study is made viable by the atomically smooth nature of the cleaved muscovite mica surface.…”

Section: Introductionmentioning

confidence: 99%

An Electrokinetic Study of the Adsorption of Dodecyl Ammonium Amine Surfactants at the Muscovite Mica−Water Interface

et al. 1999

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The adsorption of dodecyl single chain surfactants with primary, secondary, tertiary, and quaternary ammonium headgroups at the muscovite mica basal plane-water interface has been investigated using a flat plate streaming potential apparatus and atomic force microscopy (AFM). Both a hemi-micelle concentration (HMC) and a point of zeta potential reversal (PZR) were observed as the surfactant adsorbed at the muscovite mica-water interface. The HMC and PZR were shifted to higher surfactant concentration as the headgroup was changed from the primary to the quaternary ammonium group. AFM images of surfactant patches adsorbed at the mica-water interface indicate that the surfactant patch size becomes smaller and distributes more uniformly with change from the primary to quaternary ammonium headgroups. The hydrophobic force contribution of the hydrocarbon chain to the adsorption of the C12 surfactant, estimated by subtracting other contributions from the total adsorption free energy, was calculated to decrease as the headgroup was changed from the primary to the quaternary amine.

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“…around pH 10.5-11 [22,23]. Coagulation of such particles around this pH on to quartz surfaces [12,24] is not accompanied by a strong interaction with the solid. At pH values higher than 9, quartz flotation with dodecylamine is depressed.…”

Section: Discussionmentioning

confidence: 99%

“…Claesson and his colleagues [24,25] used a surface force apparatus to study interactions between smooth mica surfaces in aqueous solutions of docecylammonium chloride. Mica is a highly negatively charged homogenous surface and is commonly used in the surface forces measurements.…”

Section: Discussionmentioning

confidence: 99%

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Flotation of Sulfide Minerals with the use of a Cationic Collector

Laskowski¹,

Yuan²

2002

Canadian Metallurgical Quarterly

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In the flotation of Zn-Pb ores, sphalerite is floated following activation with copper sulfate. In this type of sulfide ore, pyrite is commonly treated as a gangue and poor selectivity between sphalerite and pyrite/quartz is often reported. But pyrite may also appear in association with gold and flotation of such auriferous sulfides is of great importance in many countries such as South Africa and Australia.In the cationic flotation of sulfide ores with dodecyl amine, sphalerite can be floated while depressing quartz and pyrite. While in a well-aerated pulp in the presence of lime (especially after oxidation with H 2 O 2 ) the cationic flotation of pyrite is depressed, oxidation of pyrite in the presence of Na 2 S makes it floatable with amines even in a very alkaline environment.Résumé -Au cours de la flottation de minerais de Zn-Pb, on fait flotter la galène par activation avec du sulfate de cuivre. Dans ce genre de minerai de sulfure, on traite communément la pyrite comme une gangue alors qu'on rapporte souvent une faible sélectivité entre la galène et la pyrite/quartz. Cependant, la pyrite peut aussi être associée avec l'or et la flottation de tels sulfures aurifères est d'une grande importance dans plusieurs pays (e. g. Afrique du Sud, Australie).Dans la flottation cationique des minerais de sulfure avec du dodécylamine, on peut faire flotter la galène tout en déprimant le quartz et la pyrite. Lorsque dans une pulpe bien aérée en présence de chaux (spéciale-ment après oxydation avec du H 2 O 2 ), la flottation cationique de la pyrite est déprimée, l'oxydation de la pyrite en présence de Na 2 S la rend flottable avec des amines, même dans un environnement très alcalin.

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Amine functionalized surfactants — pH effects on adsorption and interaction

Cited by 12 publications

References 28 publications

Direct Surface Force Measurements of Polyelectrolyte Multilayer Films Containing Nanocrystalline Cellulose

Direct Surface Force Measurements of Polyelectrolyte Multilayer Films Containing Nanocrystalline Cellulose

An Electrokinetic Study of the Adsorption of Dodecyl Ammonium Amine Surfactants at the Muscovite Mica−Water Interface

Flotation of Sulfide Minerals with the use of a Cationic Collector

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