Interfacial Free Energy of Alkanols in Aqueous Solutions: Dependence with Hydrophobicity and Topology of the Solute

Aspée, Alexis; Lissi, E. A.

doi:10.1006/jcis.1996.0117

Cited by 9 publications

(11 citation statements)

References 7 publications

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“…Our simulations show that lower bulk concentrations of linear surfactants than branched ones are needed to obtain the same interfacial tension reduction. This is in agreement with the results of Aspée and Lissi, who concluded that when the surface coverage is high enough for steric repulsion to be important, branched isomers of nonanol will have a higher free energy at the interface. Our results agree also qualitatively with experimental work on Guerbet branched surfactants with ionic or nonionic head groups .…”

Section: Resultssupporting

confidence: 93%

“…Aspée and Lissi, investigating alcohols of different topology and chain lengths, concluded that the branched isomers have a larger tendency to adsorb at the interface at low surface pressures, whereas linear surfactants are more efficient at higher surface pressure. 7 Although the interfacial tension measurements are relatively straightforward, it is difficult to obtain detailed information on the behavior of the amphiphilic molecules and their concentration at the interface as this requires expensive neutron scattering experiments.…”

Section: Introductionmentioning

confidence: 99%

“…Whereas, for example, the effect of increasing tail length on the interfacial tension is well-known and understood (Traube's rule), , there are no such clear rules concerning the effect of branching the hydrophobic tail. Although Rosen 1 summarizes that linear surfactants are more efficient than branched isomers, both positive , and negative , effects of branching on surfactant efficiency are reported in the literature and the effect is still not fully understood.…”

Section: Introductionmentioning

confidence: 99%

“…Further branching was found to lower the efficiency significantly ,, due to a less compact monolayer. Aspée and Lissi, investigating alcohols of different topology and chain lengths, concluded that the branched isomers have a larger tendency to adsorb at the interface at low surface pressures, whereas linear surfactants are more efficient at higher surface pressure …”

Section: Introductionmentioning

confidence: 99%

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Investigation of Surfactant Efficiency Using Dissipative Particle Dynamics

et al. 2003

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We have used dissipative particle dynamics (DPD) to simulate surfactant monolayers on the interface between oil and water. With a simple surfactant model, we investigate how variations in size and structure of surfactants influence their ability to reduce the interfacial tension. In particular, we studied the effect of branching of the hydrophobic tail. We found that branched surfactants are more efficient at the interface than linear ones only if the head groups are sufficiently hydrophilic to prevent the molecules from staggering. By combining DPD with a Monte Carlo method, we have imposed constant surfactant chemical potential and (normal) pressure in separate simulations of bulk and interface. From this, we can determine the bulk concentration needed to obtain a given interfacial tension. We found that higher concentrations of branched surfactants are required to obtain the same reduction of the interfacial tension. We argue that the stronger excluded volume interactions which make branched surfactants more efficient at the interface compared to their linear isomers at the same time make them less inclined to adsorb at the interface.

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Section: Resultssupporting

confidence: 93%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Investigation of Surfactant Efficiency Using Dissipative Particle Dynamics

et al. 2003

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“…These studies agree on the fact that surfactants with two hydrophobic chains are less efficient in reducing the interfacial tension compared to their single-tail isomers. Experimentally, however, either more, equal, or less efficient branched surfactants are reported, depending on the details of the experimental setup [3,[5][6][7][8]. …”

mentioning

confidence: 99%

Effect of surfactant structure on interfacial properties

Rekvig¹,

Kranenburg²,

Hafskjold³

et al. 2003

Europhys. Lett.

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PACS. 82.70.Uv -Surfactants, micellar solutions, vesicles, lamellae, amphiphilic systems (hydrophilic and hydrophobic interactions). PACS. 68.05.-n -Liquid-liquid interfaces.Abstract. -We study surfactants at the oil/water interface using Dissipative Particle Dynamics simulations at constant µ surf P T . The interfacial tension depends on the surfactant branching in a subtle way. For a given interfacial concentration, a double-tail surfactant is more efficient than its single-tail isomer only if the oil-head repulsion is sufficiently strong. For a given concentration in the bulk water phase, the single-tail surfactants are more efficient in both cases. We interpret these results in light of the molecular packing at the interface and free-energy considerations.Introduction. -Surfactants are molecules that consist of hydrophobic and hydrophilic parts. Their amphiphilic nature makes them surface active and, adsorbed at the oil/water interface, they can reduce the bare oil-water interfacial tension to very low values. Because of this property, surfactants are used in many practical applications ranging from crude oil recovery to state-of-the-art drug delivery [1] and are also of scientific interest. From a practical viewpoint, it is important to understand how the efficiency in reducing the interfacial tension is related to the structure of a surfactant. This question was already posed by Traube in 1899 [2] and he discovered that increasing the hydrophobic tail length results in surfactants that are more efficient (Traube's rule). At present, the effect of branching of the hydrophobic tail is not yet fully understood, despite the fact that many of the surfactants used in industrial applications are prepared with branched hydrocarbon tails. The effect of branching on the interfacial tension was investigated by self-consistent field calculations [3] and molecular-dynamics simulations on model surfactants [3,4]. These studies agree on the fact that surfactants with two hydrophobic chains are less efficient in reducing the interfacial tension compared to their single-tail isomers. Experimentally, however, either more, equal, or less efficient branched surfactants are reported, depending on the details of the experimental setup [3,[5][6][7][8].

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Regarding the effect that different twin-tailed surfactant have on a solid stabilized petroleum emulsion

et al. 2007

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An industrial petroleum emulsion stabilized by colloidal silica particles was treated with four different twin-tailed surfactants: sodium bis-2-(ethylhexyl) sulfosuccinate (AOT), didodecylammonium bromide (DDAB), calcium oleate (Ca(OL) 2 ), and dioctadecyldimethylammonium bromide (DODAB). Fourier transform infrared (FT-IR) spectroscopy, optical microscopy, centrifuge test, and conductivity measurement were employed to determine the effect of the amphiphile molecules on the crude oil emulsion. AOT and DDAB produce emulsion breakdown, while Ca(OL) 2 does not alter the emulsion stability and DODAB produces an extra stabilization of it. The AOT adsorption at the oilwater droplet interface is a spontaneous process (ΔH ads <0), which promoted the emulsion breakdown through an interdroplet interaction mechanism. DDAB needs extra energy (via centrifugation) to destabilize the emulsion. Ca(OL) 2 dissolves in oil phase and remains there without altering the emulsion strength, while DODAB increases the emulsion stability.

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Interfacial Free Energy of Alkanols in Aqueous Solutions: Dependence with Hydrophobicity and Topology of the Solute

Cited by 9 publications

References 7 publications

Investigation of Surfactant Efficiency Using Dissipative Particle Dynamics

Investigation of Surfactant Efficiency Using Dissipative Particle Dynamics

Effect of surfactant structure on interfacial properties

Regarding the effect that different twin-tailed surfactant have on a solid stabilized petroleum emulsion

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