Permeability of Newtonian black foam films to gas

Abstract

The gas permeability of Newtonian black foam films, formed on the top of a small bubble at the solution surface, was studied experimentally. The aqueous solutions contained sodium dodecylsulphate with concentrations in the range 1.5 x 10 -4 to 3 • 10 -3 mol/dm 3 and sodium chloride (constant concentration of 0.5 mol/dm3). A dependence of the gas permeability coefficient on the surfactant concentration was obtained. The experimental results are discussed on the basis of a theory assuming the presence of clusters of molecule vacancies (holes) in the bilayer foam film, their number and size depending on the surfactant concentration. The experimental results are in agreement with this film structure and confirm the existence of flow through both the hole-free bilayer film and the holes. It was found that the holes of three molecule vacandes make the main contribution to gas permeability at low surfactant concentration. The diffusion coefficients through the hole-free film and through the three-vacancy holes are calculated.

A simulation study of the kinetics of passage of CO2 and N2 through the liquid/vapor interface of water

“…The permeation rates of thin soap films have been thoroughly investigated; see, for example, the review by Exerowa et al 15 It was established that the permeability is dependent on temperature, the type of electrolyte, type of surfactant, and their concentrations. [16][17][18][19][20][21] The thinnest soap films, known as Newton black films, consist of two surfactant monolayers absorbed onto each other. Somewhat thicker thin soap films, for which the monolayers are separated by a water layer, are known as common black films.…”

In situ measurement of the permeability of foam films using quasi-two-dimensional foams

“…Many different experiments have been developed in the past aiming to measure the permeability of an isolated film ( [3] and references therein). These include in particular the "bubble diminishing method" [4][5][6][7] and a variant in which a pressure gradient across the film can be imposed explicitly [8][9][10][11]. We can also cite experiments performed in 1D-foams (bamboo foams: collection of bubbles in a tube) [12].…”

Impact of Fluorocarbon Gaseous Environments on the Permeability of Foam Films to Air

“…In the literature, the permeability of a film to a given gas is generally measured by following the deflation of a bubble deposited on the surface of a bath when driven by Laplace overpressure. [13][14][15] A value of the film permeability is inferred by solving a nonsteady equation for the transferred gas volume. [15][16][17][18][19][20][21][22] The permeabilities measured in this way have been found to depend on different parameters: temperature, 16 gas and film composition.…”

“…[13][14][15] A value of the film permeability is inferred by solving a nonsteady equation for the transferred gas volume. [15][16][17][18][19][20][21][22] The permeabilities measured in this way have been found to depend on different parameters: temperature, 16 gas and film composition. 18,20,21,[23][24][25][26][27] However, during the deflation of the bubble, the thickness of the soap film through which gas exchange takes place is neither homogeneous nor stationary.…”