Structure of adsorption layers of ionic surfactants at the solid/liquid interface

Rupprecht, H.; Gu, Tingyue

doi:10.1007/bf00655889

Cited by 134 publications

(91 citation statements)

References 47 publications

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“…The maximum amount adsorbed (9.3 µmol/m 2 for the adsorption of SDS) corresponds to a charge density eight times higher than the charge on the latex surface. It suggests that small associates of surfactant molecules are formed on the surface by hydrophobic interaction between the hydrocarbon chains (25). Thus, hydrophobic interaction plays an important role even when the surface and surfactant have opposite charges.…”

Section: Resultsmentioning

confidence: 99%

Sequential Adsorption of Triton X-100 and Sodium Dodecyl Sulfate onto Positively and Negatively Charged Polystyrene Latexes

Porcel

Jódar

Cabrerizo

et al. 2001

Journal of Colloid and Interface Science

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Individual and sequential adsorption of the anionic surfactant sodium dodecyl sulfate (SDS) and the nonionic surfactant Triton X-100 on cationic and anionic polystyrene latexes has been examined. Both latex samples, although charged differently (−16.2 and +11.0 µC cm −2 ), must be considered hydrophobic polymer colloids. The adsorbed amounts of both surfactants on cationic and anionic latexes were found to be different as a consequence of the dissimilar interfacial properties of these two surfactants. In addition, a comparison between the two surfactants showed that SDS is more easily replaced than Triton X-100 when sequential adsorption on both latexes was studied. It was found that the electrophoretic mobility of surfactant latex complexes depends on the addition sequence order of both surfactants. In relation to colloidal stability, when a layer of a nonionic surfactant is adsorbed on the surface of latexes, the electrosteric mechanism explains the experimental results. If SDS is adsorbed the stabilization or unstabilization is a consequence of the changes in the electrical repulsion between particles. However, when both surfactants are adsorbed, the assumption of additivity is not correct; that is, the electrostatic repulsion (V R ) and the steric repulsions (V osm and V vr ) are not totally independent. C 2001 Academic Press Key Words: cationic and anionic polymer colloids; nonionic and anionic surfactant adsorption; sequential adsorption; colloidal stability.

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Section: Resultsmentioning

confidence: 99%

Sequential Adsorption of Triton X-100 and Sodium Dodecyl Sulfate onto Positively and Negatively Charged Polystyrene Latexes

Porcel

Jódar

Cabrerizo

et al. 2001

Journal of Colloid and Interface Science

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“…Thus, Tsaur and Fitch [28] reported the formation of large amounts of polyelectrolyte in solution when the concentration of anionic surfmer (sodium sulfodecylstyryl ether) was above the CMC. The rates are even higher if the mobility of the surfmer molecules is further reduced, e. g. when they form admicelles [102] (the basic difference between micelles and admicelles is that micelles are subjected to a rapid exchange of surfactant molecules with the medium [103], whereas admicelles are formed by adsorption of the surfactant to a solid surface and are relatively fixed to the solid surface [104] with larger aggregation numbers [105]). This can have consequences for the polymerization of the surfmer adsorbed on the polymer particles (see below).…”

Section: Polymerization Locimentioning

confidence: 97%

Reactive surfactants in heterophase polymerization

Asúa¹,

Schoonbrood²

1998

Acta Polym.

134

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“…Isolated surfactant anions sporadically anchored on the particle edges act as nuclei for the clustering of additional surfactant anions (Rupprecht andGu 1991, see also Lagaly 1994b) (Figure 7). Formation of these small surface aggregates increases the negative charge density at the edges.…”

Section: Salt Stabilitymentioning

confidence: 98%

The Rheological and Colloidal Properties of Bentonite Dispersions in the Presence of Organic Compounds V. Bentonite and Sodium Montmorillonite and Surfactants

Permien

Lagaly

1995

Clays and clay miner.

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Abstract--The influence of surfactants on the flow behavior of sodium montmorillonite dispersions (2% w/w) was studied for a cationic (cetylpyridinium chloride, CPC1) and an anionic surfactant (sodium dodecylsulfate, SDS). When the dispersion pHs were >3.5 and <7, CPC1 concentrations >10 -4 M increased the shear stress but the Bingham yield value remained virtually unchanged (to ~-100 mPa). At pH ~ 7, the shear stress and yield point decreased with increasing CPC1 concentration (70 from 430 to 100 mPa). The flow properties of sodium calcium bentonite dispersions were independent of pH and CPCI concentrations -< 10 -4 M; they increased modestly at higher concentrations. At pH < 4, SDS addition to the sodium montmorillonite dispersions increased the shear stress and yield value to a maximum value (to = 2100 mPa) at 10 -3 M SDS; higher SDS concentrations reduced the shear stress and yield value. At pH > 4, the flow values decreased to a minimum value at 10 -2 M SDS (to from 430 to 50 mPa). The flow of the sodium calcium bentonite dispersions at pH > 4 was independent of SDS concentrations -< 10 -3 mole/liter; at higher SDS concentrations, the flow values increased more strongly in sodium calcium bentonite than in sodium montmorillonite dispersions.Surfactants influence the flow behavior of sodium montmorillonite dispersions by their action on the card-house networks in strongly acidic medium and, at higher pH, by the electroviscous effect. At the highest surfactant concentrations without flocculation, the shear stress and yield value are increased by interacting chains of opposed particles.Addition of the surfactants increases the salt (NaC1) stability of the dispersions because the adsorbed surface active agents influence the counterion distribution between the Stern and the diffuse ionic layer.

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Structure of adsorption layers of ionic surfactants at the solid/liquid interface

Cited by 134 publications

References 47 publications

Sequential Adsorption of Triton X-100 and Sodium Dodecyl Sulfate onto Positively and Negatively Charged Polystyrene Latexes

Sequential Adsorption of Triton X-100 and Sodium Dodecyl Sulfate onto Positively and Negatively Charged Polystyrene Latexes

Reactive surfactants in heterophase polymerization

The Rheological and Colloidal Properties of Bentonite Dispersions in the Presence of Organic Compounds V. Bentonite and Sodium Montmorillonite and Surfactants

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