Electrokinetic study of adsorption of ionic surfactants on titania from organic solvents

Kosmulski, Marek; Próchniak, Piotr; Rosenholm, Jarl B.

doi:10.1016/j.colsurfa.2009.06.033

Cited by 14 publications

(11 citation statements)

References 8 publications

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“…The classification of solvents by the adsorption preference for cation or anion of ionic surfactants introduced in the previous study [8] and the concept of borderline solvents were confirmed to be qualitatively correct. Apparently the water-like or oil-like adsorption preference is rather insensitive to the nature of solid particles.…”

Section: Discussionsupporting

confidence: 56%

“…Mixed water-organic solvents [5][6][7] have been used to study the effect of solvent polarity on the adsorption behavior of surfactants. More recently [8] we found that the borderline between two extreme adsorption behaviors of surfactants occurs in solvents with dielectric constants of about 25 using a series of anhydrous solvents. These studies were carried out by means of electrophoresis, that is, at low solid-to-liquid ratio.…”

Section: Introductionmentioning

confidence: 99%

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Solvents, in which ionic surfactants do not affect the zeta potential

Kosmulski

Próchniak

Rosenholm

2010

Journal of Colloid and Interface Science

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Section: Discussionsupporting

confidence: 56%

Section: Introductionmentioning

confidence: 99%

Solvents, in which ionic surfactants do not affect the zeta potential

Kosmulski

Próchniak

Rosenholm

2010

Journal of Colloid and Interface Science

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“…In solvents with intermediate polarities (e r E 25), changing surfactant concentration has little effect on the charge of the particles. 27,28 The same effect has been observed for the aggregation of surfactants in solvents of widely different polarities; there is a region of intermediate ''solvent quality'' where no significant aggregation occurs. 29 In this review, the nature of the surfactants in nonpolar solvents and their role in introducing charge into these systems will be considered.…”

Section: Introductionsupporting

confidence: 55%

Controlling colloid charge in nonpolar liquids with surfactants

Smith

Eastoe

2013

Phys. Chem. Chem. Phys.

146

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The formation of ions in nonpolar solvents (with relative permittivity ε r of approximately 2) is more difficult than in polar liquids; however, these charged species play an important role in many applications, such as electrophoretic displays. The low permittivities (ε r) of these solvents mean that charges have to be separated by large distances to be stable (approximately 28 nm or 40 times that in water). The inverse micelles formed by surfactants in these solvents provide an environment to stabilize ions and charges. Common surfactants used are sodium dioctylsulfosuccinate (Aerosol OT or AOT), polyisobutylene succinimide, sorbitan oleate, and zirconyl 2-ethyl hexanoate. The behavior of charged inverse micelles has been studied on both the bulk and on the microscopic scale and can be used to determine the motion of the micelles, their structure, and the nature of the electrostatic double layer. Colloidal particles are only weakly charged in the absence of surfactant, but in the presence of surfactants, many types, including polymers, metal oxides, carbon blacks, and pigments, have been observed to become positively or negatively charged. Several mechanisms have been proposed as the origin of surface charge, including acid-base reactions between the colloid and the inverse micelle, preferential adsorption of charged inverse micelles, or dissolution of surface species. While most studies vary only the concentration of surfactant, systematic variation of the particle surface chemistry or the surfactant structure have provided insight into the origin of charging in nonpolar liquids. By carefully varying system parameters and working to understand the interactions between surfactants and colloidal surfaces, further advances will be made leading to better understanding of the origin of charge and to the development of more effective surfactants.

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“…Measurements of zeta potentials for TiO 2 particles in hexane in the presence of surfactant indicate surface charge densities on the order of –0.1 μC cm –2 , which is much lower than the surface charge density for ferroelectric nanoparticles. 24 The small change in selectivity observed upon attachment of 4b to nonferroelectric nanoparticles may arise from the interaction of the catalyst with the oxide surface or a subtle conformational biasing for attached catalysts. 25 , 26 When 4b was attached to ferroelectric PbTiO 3 , the ratio was 5.3 : 1.0, which was only slightly lower than the other non-ferroelectric oxides.…”

Section: Resultsmentioning

confidence: 99%