Zur Methodik der Ultramikro-Elektrophorese

Gils, G. E. van; Kruyt, H. R.

doi:10.1007/bf02556031

Cited by 50 publications

(5 citation statements)

References 14 publications

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“…The latter instrument enabled us to determine the mobility of the particles at various cell depths. A van Gils plot then allowed the mobility at the stationary levels to be known. The measurements were repeated at least four times, using a new solution each time, and their average was taken.…”

Section: Methodsmentioning

confidence: 99%

Interaction Forces and Zeta Potentials of Cationic Polyelectrolyte Coated Silica Surfaces in Water and in Ethanol: Effects of Chain Length and Concentration of Perfluorinated Anionic Surfactants on Their Binding to the Surface

et al. 2001

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Silica surfaces were premodified by the saturated adsorption of the cationic polyelectrolyte of poly(2-vinyl-1-methyl-pyridinium bromide), P2VP, in water. The interaction forces between and the zeta potential of the silica surfaces were then measured in water and in ethanol solutions of perfluorinated anionic surfactants as a function of their chain length and concentration using the AFM surface force and electrophoresis methods. In water, the electrostatic repulsive forces between P2VP-modified silica surfaces in CF3CF2COONa, CF3(CF2)6COONa, and CF3(CF2)7SO3Li solutions of 0.1 mM were identical to the force curve in 0.1 mM NaNO3 but greatly decreased in 0.1 mM CF3(CF2)9COOLi (critical micelle concentration (cmc), 0.39 mM). The concentration increase of CF3(CF2)7SO3Li (cmc, 6.3 mM) from 0.1 to 1.0 mM caused the repulsive force curves to weaken and then to strengthen after passing through a zero repulsive force. The surface potentials obtained by the best curve fitting of the force curves agreed well with the zeta potentials, which indicated a surface charge reversal from positive to negative for a high concentration of CF3(CF2)7SO3Li. These observations were explained by the formation of a Stern layer due to specific counterion binding of the surfactant anions, which increased with the surfactant chain length and concentration. In ethanol, CF3(CF2)7SO3Li always showed strong repulsive force curves, when CF3(CF2)7SO3Li concentrations that were adjusted to give identical Debye lengths as those in water were used and the surface charge of P2VP-modified silica was the same as that in water. The surface potential obtained by the best curve fitting coincided with the zeta potential of positive sign, confirming no charge reversal. This suggested no obviously firm formation of a Stern layer by the surfactant ions. This was not always the case for shorter carbon-chain surfactants, since CF3(CF2)6COONa revealed a much weaker repulsive force curve than CF3(CF2)7SO3Li for concentrations of identical Debye lengths. This was explained in terms of an increased surfactant binding, due to the polarity difference between the solvent and surfactant molecules.

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Section: Methodsmentioning

confidence: 99%

Interaction Forces and Zeta Potentials of Cationic Polyelectrolyte Coated Silica Surfaces in Water and in Ethanol: Effects of Chain Length and Concentration of Perfluorinated Anionic Surfactants on Their Binding to the Surface

et al. 2001

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“…Electrokinetic Measurements. Zeta-potentials of particles and substrates were determined by microelectrophoresis, using both a cylindrical glass cell of the van Gils type (van Gils and Kruyt, 1936; Kruyt, 1952) and a flat cell apparatus mounted vertically, made from a fused silica spectrophotometer cell of length 45 mm., height 10 mm., width (optical path) 1 mm., similar to that described elsewhere by McGown, tt al. (1965).…”

Section: Methodsmentioning

confidence: 99%

Adhesion and detachment of solid colloidal particles in aqueous ionogenic surfactant media

Clayfield¹,

Smith²

1970

Environ. Sci. Technol.

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The adhesion of carbon black particles to a glass substrate in aqueous media and their subsequent removal by ionic surfactant solutions have been studied by a powder-bed technique and by direct microscopic observation. The electrostatic interaction between the colloidal particles and the substrate was varied by changing the concentrations of surfactant and indifferent electrolyte present in the system. It was shown that considerable removal of adhered particles could be obtained, with no appreciable hydrodynamic displacement action being required; this "spontaneous" detachment of solid colloidal particles thus provides an aqueous analog of the corresponding phenomenon found to occur in nonaqueous media. The experimental results have been considered in conjunction with the electrokinetic potentials of both surfaces, and an explanation offered in terms of electrical double layer theory and the "secondary minimum" adhesion concept.

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“…The apparatus used was based on the earlier design of van Gils and Kruyt, and Kruyt and Troelstra. 3 The microcell was constructed from a thin cylindrical Pyrex tube of diameter 2.74 mm (wall thickness 0.19 mm) and the design was such that washing, emptying and filling of the cell could easily be carried out iu situ. The electrodes used were spirals of thin platinized platinum wire, which were sealed into soda glass.…”

Section: Microelectrophoresis Apparatusmentioning

confidence: 99%

The stability of hydrophobic sols in the presence of surface-active agents. Part 3.—An examination by microelectrophoresis of the behaviour of silver iodide sols in the presence of cationic surface-active agents

Ottewill¹,

Rastogi²

1960

Trans. Faraday Soc.

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Zur Methodik der Ultramikro-Elektrophorese

Cited by 50 publications

References 14 publications

Interaction Forces and Zeta Potentials of Cationic Polyelectrolyte Coated Silica Surfaces in Water and in Ethanol: Effects of Chain Length and Concentration of Perfluorinated Anionic Surfactants on Their Binding to the Surface

Interaction Forces and Zeta Potentials of Cationic Polyelectrolyte Coated Silica Surfaces in Water and in Ethanol: Effects of Chain Length and Concentration of Perfluorinated Anionic Surfactants on Their Binding to the Surface

Adhesion and detachment of solid colloidal particles in aqueous ionogenic surfactant media

The stability of hydrophobic sols in the presence of surface-active agents. Part 3.—An examination by microelectrophoresis of the behaviour of silver iodide sols in the presence of cationic surface-active agents

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