Foams

Saint‐Jalmes, Arnaud; Durian, Douglas J.; Weitz, David A.

doi:10.1002/0471238961.0615011304211809.a01.pub2

Cited by 6 publications

(5 citation statements)

References 87 publications

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“…7), and to typical Plateau border radii reaching typically tens of microns (for the initial bubble size used here). [1][2][3][4] The observed collapse of the foams shows that the repulsion between the interfaces of the lms separating bubbles can only support low capillary suctions, but cannot counterbalance the high capillary suction occurring as the foams drain. This is most likely due to the nature of the repulsive forces providing the disjoining pressure, and also to their spatial uniformity.…”

Section: Discussionmentioning

confidence: 99%

“…Because surfactants modify the interfaces in such ways, they are crucial for producing and stabilizing all types of liquid dispersions (like foams and emulsions) in various applications and elds like cosmetics, detergency, or in the food industry. [1][2][3] Surfactants not only help for the formation of a liquid dispersion, but many macroscopic properties of such dispersions are directly linked to the interfacial structural and dynamical properties, driven by the chemical formulation at the interfaces. 4,5 Beside dispersed materials, it has recently emerged that the dynamics of processes involving single liquid lms or free interfaces are controlled by the coupling between bulk and interfacial hydrodynamics.…”

Section: Introductionmentioning

confidence: 99%

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Dynamics of poly-nipam chains in competition with surfactants at liquid interfaces: from thermoresponsive interfacial rheology to foams

Guillermic

Saint‐Jalmes

2013

Soft Matter

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We report results on the interfacial viscoelasticity and foaming of solutions of a thermoresponsive polymer (poly-n-isopropylacrylamide) with and without added surfactants, and as a function of temperature. With pure polymer solution, a clear transition is evidenced: both interfacial shear and dilational rheology shift from a fluid-like to a solid-like behavior at a well-defined temperature. The high temperature regime shows that the layer shares many features with soft glassy systems. At all temperatures, the foaming is low and the foam produced is unstable. Adding a surfactant not only helps to foam and to stabilize the foam, but also removes the thermal responsivity of the interfacial viscoelasticity. Under the conditions used here, we observe that the surfactant concentration threshold for altering the high temperature interfacial viscoelasticity is low, and is of the order of 1% of the surfactant critical micelle concentration.It turns out to be very different from critical values for the polymer-surfactant association found previously by structural studies (in bulk and at interface), and also below the threshold value required to stabilize the foam.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Dynamics of poly-nipam chains in competition with surfactants at liquid interfaces: from thermoresponsive interfacial rheology to foams

Guillermic

Saint‐Jalmes

2013

Soft Matter

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“…If the timescale for surfactant diffusion and adsorption is shorter than the hydrodynamic timescale that creates the γ gradients, then the Marangoni resistance to the drainage of the foam will be lowered . This scenario arises when the surfactant is very soluble in the dispersed phase, where the diffusion length to the lamellae is small.…”

Section: Discussionmentioning

confidence: 99%

Morphology and Stability of CO₂-in-Water Foams with Nonionic Hydrocarbon Surfactants

Adkins¹,

Chen²,

Chan³

et al. 2010

Langmuir

134

139

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The morphologies, stabilities, and viscosities of high-pressure carbon dioxide-in-water (C/W) foams (emulsions) formed with branched nonionic hydrocarbon surfactants were investigated by in situ optical microscopy and capillary rheology. Over two dozen hydrocarbon surfactants were shown to stabilize C/W foams with Sauter mean bubble diameters as low as 1 to 2 microm. Coalescence of the C/W foam bubbles was rare for bubbles larger than about 0.5 microm over a 60 h time frame, and Ostwald ripening became very slow. By better blocking of the CO(2) and water phases with branched and double-tailed surfactants, the interfacial tension decreases, the surface pressure increases, and the C/W foams become very stable. For branched surfactants with propylene oxide middle groups, the stabilities were markedly lower for air/water foams and decane-water emulsions. The greater stability of the C/W foams to coalescence may be attributed to a smaller capillary pressure, lower drainage rates, and a sufficient surface pressure and thus limiting surface elasticity, plus small film sizes, to hinder spatial and surface density fluctuations that lead to coalescence. Unexpectedly, the foams were stable even when the surfactant favored the CO(2) phase over the water phase, in violation of Bancroft's rule. This unusual behavior is influenced by the low drainage rate, which makes Marangoni stabilization of less consequence and the strong tendency of emerging holes in the lamella to close as a result of surfactant tail flocculation in CO(2). The high distribution coefficient toward CO(2) versus water is of significant practical interest for mobility control in CO(2) sequestration and enhanced oil recovery by foam formation.

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“…Foam, meaning ''bubbly liquid'', is obtained when a non-equilibrium dispersion of gas bubbles in a relatively small volume of liquid containing surfactants exists [1]. These surface active macromolecules adsorb at the gas/liquid interfaces and are responsible for both the tendency of a liquid to foam and the stability of the resulting dispersion [2,3].…”

Section: Introductionmentioning

confidence: 99%

Foamability of Detergent Solutions Prepared with Different Types of Surfactants and Waters

Amaral

Neves

Oliveira

et al. 2008

J Surfact & Detergents

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In the development of new detergent products, it is important to test the foaming behavior of different types of surfactants. Different types and concentrations of surfactant solutions prepared with three types of water are expected to present differences in their foamability. In this study, foam volumes produced by cetyl trimethyl ammonium bromide (CTAB; C 19 H 42 BrN), Tween 80 Ò (T80; C 64 H 124 O 26 ) and sodium dodecylsulfate (SDS; C 12 H 25 NaO 4 S) aqueous solutions (0.5, 1.0 and 1.5%, w/v) were compared using a stirring system, rotating at 8,000, 9,500 and 13,500 rpm. The foamability produced by CTAB, SDS and T80 solutions, in a concentration range between 0.2 and 1.0% (w/v), prepared using deionized, hard and hypersaline water were also compared. Foam volumes were higher at a stirring speed of 9,500 rpm than at 8,000 rpm. However, the results obtained at 9,500 and 13,500 rpm were not significantly different. In general, SDS solutions produced higher foam volumes than CTAB and T80 solutions. Water characteristics did not seem to influence significantly the foamability of the three types of surfactants in the studied concentrations. These studies related with foaming behavior appear to be an important step in the pre-formulation of detergent products, particularly in cosmetics and pharmaceutics.

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Foams

Cited by 6 publications

References 87 publications

Dynamics of poly-nipam chains in competition with surfactants at liquid interfaces: from thermoresponsive interfacial rheology to foams

Dynamics of poly-nipam chains in competition with surfactants at liquid interfaces: from thermoresponsive interfacial rheology to foams

Morphology and Stability of CO₂-in-Water Foams with Nonionic Hydrocarbon Surfactants

Foamability of Detergent Solutions Prepared with Different Types of Surfactants and Waters

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Foams

Cited by 6 publications

References 87 publications

Dynamics of poly-nipam chains in competition with surfactants at liquid interfaces: from thermoresponsive interfacial rheology to foams

Dynamics of poly-nipam chains in competition with surfactants at liquid interfaces: from thermoresponsive interfacial rheology to foams

Morphology and Stability of CO2-in-Water Foams with Nonionic Hydrocarbon Surfactants

Foamability of Detergent Solutions Prepared with Different Types of Surfactants and Waters

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Morphology and Stability of CO₂-in-Water Foams with Nonionic Hydrocarbon Surfactants