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Journal ArticleDOI

Free drainage of aqueous foams stabilized by mixtures of a non-ionic (C12DMPO) and an ionic (C12TAB) surfactant

TL;DR: In this paper, the influence of the composition of a surfactant mixture on free drainage of the respective foams was investigated using Foam Conductivity Apparatus (FCA).
About: This article is published in Colloids and Surfaces A: Physicochemical and Engineering Aspects.The article was published on 2013-02-20. It has received 27 citations till now. The article focuses on the topics: Pulmonary surfactant.
Citations
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Journal ArticleDOI
TL;DR: In this paper, an attempt has been paid to design the suitable foaming agents (foamer) by evaluating the influence of three surfactants, five nanoparticles and several additives.

95 citations

Journal ArticleDOI
TL;DR: In this paper, a foam stabilizer including polyvinyl alcohol (PVA) polymer, two different surfactants, and six different nanoparticles was used to stabilize the foam.

54 citations

Journal ArticleDOI
TL;DR: It is shown that unknown double-layer potentials at the liquid–gas interface from solutions with different C16TAB/C10E4 mixing ratios can be obtained from an analysis of SFG spectra and are in excellent agreement with the complementary results from the TFPB technique.
Abstract: Vibrational sum-frequency generation (SFG) spectroscopy is demonstrated as a fast method to quantify variations of the electric double-layer potential ϕ0 at liquid–gas interfaces. For this, mixed s...

44 citations

Journal ArticleDOI
TL;DR: In this article, the authors examined how low surfactant concentration affects foam destabilization and elucidate the interplay between free drainage and bubble size variation, showing that moderately stable foams depend largely on surfactants below the critical micelle concentration (SDS).

44 citations

Journal ArticleDOI
TL;DR: A systematic foaming study of two types of surfactants found that stable foams are obtained when the head group is capable of forming intersurfactant H-bonds, suggesting that hydrogen bonds between neighbouring molecules at the surface enhance foam stability.

33 citations

References
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Journal ArticleDOI
30 Jun 2000-Langmuir
TL;DR: In this paper, a new experimental method is presented using fluorescein dye to determine the spatial and temporal variations of the liquid volume fraction in aqueous foams This method was used for quantitative studies of liquid redistribution (drainage) in three types of experiments: forced, free, and pulsed drainage Characteristic quantities, such as the drainage velocity, show power-law dependences on experimental parameters that are inconsistent with traditional foam drainage models based on Poiseuille-type flow in the liquid-carrying channels (Plateau borders) of the foam.
Abstract: A new experimental method is presented using fluorescein dye to determine the spatial and temporal variations of the liquid volume fraction in aqueous foams This method is used for quantitative studies of liquid redistribution (drainage) in three types of experiments: forced, free, and pulsed drainage Characteristic quantities, such as the drainage velocity, show power-law dependences on experimental parameters that are inconsistent with traditional foam drainage models based on Poiseuille-type flow in the liquid-carrying channels (Plateau borders) of the foam To obtain a theoretical description, the foam drainage equation is generalized using an energy argument which accounts for viscous dissipation in both the channels and the nodes (or vertices, which are the junctions of four channels) of the liquid network Good agreement with results for all three types of drainage experiments is found when using this new model in the limit where the dissipation is dominated by the nodes

360 citations

Journal ArticleDOI
TL;DR: In this paper, the authors review the history and recent development of this theory, analysing various exact and approximate solutions and relating them to each other, and propose a nonlinear partial differential equation for the foam density as a function of time and vertical position.
Abstract: The drainage of liquid in a foam may be described in terms of a nonlinear partial differential equation for the foam density as a function of time and vertical position. We review the history and recent development of this theory, analysing various exact and approximate solutions and relating them to each other.

283 citations

Journal ArticleDOI
TL;DR: Free-drainage experiments with slow- and fast-coarsening gases show markedly different dynamics and elucidate the importance of the coupling of the two effects.
Abstract: The evolution of a foam is determined by drainage flow of the continuous (liquid) phase and coarsening (aging) of the dispersed phase (gas bubbles). Free-drainage experiments with slow- and fast-coarsening gases show markedly different dynamics and elucidate the importance of the coupling of the two effects. Strong coarsening leads to drainage times that are shorter (accelerated drainage) and independent of the initial liquid content (self-limiting drainage). A model incorporating the physics of both drainage and diffusive coarsening shows quantitative agreement with experiment.

241 citations

Journal ArticleDOI
TL;DR: In this article, a theoretical model for interstitial liquid flow in a stationary or moving foam was devised by relating the physical structure of the foam to the physical properties of the surfactant and the foam movement.
Abstract: A theoretical model for interstitial liquid flow in a stationary or moving foam was devised by relating the physical structure of the foam to the physical properties of the surfactant and the foam movement. This was accomplished through a differential momentum balance within a typical capillary (Plateau border) of noncircular cross section with finite surface viscosity at its boundaries. Velocity profiles were then calculated and integrated numerically for the randomly oriented capillaries so as to obtain the overall liquid flow through the foam in terms of the pertinent variables. Results are presented in a form suitable for estimating concentrations and flow rates of product and waste streams in foam fractionation.

222 citations

Journal ArticleDOI
TL;DR: In this paper, the authors present an experimental study of forced drainage through a soap foam, where a constant liquid flux at the top of a dry foam produces a downwards traveling wave with a constant velocity and uniform liquid content.
Abstract: We present an experimental study of forced drainage through a soap foam, where a constant liquid flux at the top of a dry foam produces a downwards traveling wave with a constant velocity and uniform liquid content. The results are not consistent with existing models and we propose a new model, based upon relaxing the condition of wall rigidity throughout the network and emphasizing the importance of viscous damping in the nodes where Plateau borders meet. This model agrees well with the experimentally measured (power-law) scaling behavior of the drainage velocity, and the width of the propagating liquid front, on the imposed flow rate and bubble size. [S0031-9007(99)09185-1]

184 citations