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Regine Von Klitzing - One of the best experts on this subject based on the ideXlab platform.

  • Stability of Foam films of oppositely charged polyelectrolyte surfactant mixtures effect of isoelectric point
    Journal of Physical Chemistry B, 2011
    Co-Authors: N Kristenhochrein, R Miller, Andre Laschewsky, Regine Von Klitzing
    Abstract:

    In the present paper, the influence of the surfactant concentration and the degree of charge of a polymer on Foam film properties of oppositely charged polyelectrolyte/surfactant mixtures has been investigated. To verify the assumption that the position of the isoelectric point (IEP) does not change the character of the Foam film stabilities, the position of the IEP of the polyelectrolyte/surfactant mixtures has been shifted in two different ways. Within the first series of experiments, the Foam film properties were studied using a fixed surfactant concentration of 3 × 10(-5) M in the mixture. Due to the low surfactant concentration, this is a rather dilute system. In the second approach, a copolymer of nonionic and ionic monomer units was used to lower the charge density of the polymer. This gave rise to additional interactions between the polyelectrolyte and the surfactant, which makes the description of the Foam film behavior more complex. In both systems, the same characteristics of the Foam film stabilities were found: The Foam film Stability is reduced toward the IEP of the system, followed by a destabilization around the IEP. At polyelectrolyte concentrations above the IEP, Foam films are very stable. However, the concentration range where unstable films were formed was rather broad, and the mechanisms leading to the destabilization had different origins. The results were compared with former findings on PAMPS/C(14)TAB mixtures with an IEP of 10(-4) M.

  • Stability of Foam films of oppositely charged polyelectrolyte surfactant mixtures effect of isoelectric point
    Journal of Physical Chemistry B, 2011
    Co-Authors: N Kristenhochrein, R Miller, Andre Laschewsky, Regine Von Klitzing
    Abstract:

    In the present paper, the influence of the surfactant concentration and the degree of charge of a polymer on Foam film properties of oppositely charged polyelectrolyte/surfactant mixtures has been investigated. To verify the assumption that the position of the isoelectric point (IEP) does not change the character of the Foam film stabilities, the position of the IEP of the polyelectrolyte/surfactant mixtures has been shifted in two different ways. Within the first series of experiments, the Foam film properties were studied using a fixed surfactant concentration of 3 × 10–5 M in the mixture. Due to the low surfactant concentration, this is a rather dilute system. In the second approach, a copolymer of nonionic and ionic monomer units was used to lower the charge density of the polymer. This gave rise to additional interactions between the polyelectrolyte and the surfactant, which makes the description of the Foam film behavior more complex. In both systems, the same characteristics of the Foam film stabil...

  • effect of polyelectrolyte surfactant combinations on the Stability of Foam films
    Soft Matter, 2010
    Co-Authors: Nora Kristen, Regine Von Klitzing
    Abstract:

    What happens if polymers are added to a macroscopic Foam or to Foam films? This is an important question for many technical applications, but it is also important for materials and life science. This paper reviews the effect of the surface composition on the thickness and Stability of aqueous Foam films containing surfactants and polymers. The surfactant concentration is below the critical micellisation concentration (cmc) and the critical aggregation concentration (cac). The addition of polymers to Foam films leads to the formation of surface active polymer/surfactant complexes or to depletion of polymers close to the interfaces, which has a strong effect on the film Stability. The review mainly concentrates on the dilute polymer regime (below the overlap concentration c*), and results at the semi-dilute regime (above c*) are briefly reviewed. A principle concept for the relation between the surfactant/polymer combination and the film thickness and Stability is developed. It allows the prediction, of whether an unstable Newton black film (NBF) or a stable common black film (CBF) will be formed.

R Miller - One of the best experts on this subject based on the ideXlab platform.

  • β lactoglobulin adsorption layers at the water air surface 4 impact on the Stability of Foam films and Foams
    Minerals, 2020
    Co-Authors: G Gochev, R Miller, V Ulaganathan, Inga Retzlaff, Cecile Gehindelval, Deniz Z Gunes, Martin E Leser, Ulrich Kulozik, Bjorn Braunschweig
    Abstract:

    The complexity and high sensitivity of proteins to environmental factors give rise to a multitude of variables, which affect the stabilization mechanisms in protein Foams. Interfacial and Foaming properties of proteins have been widely studied, but the reported unique effect of pH, which can be of great interest to applications, has been investigated to a lesser extent. In this paper, we focus on the impact of pH on the Stability of black Foam films and corresponding Foams obtained from solutions of a model globular protein—the whey β-lactoglobulin (BLG). Foam Stability was analyzed utilizing three characteristic parameters (deviation time, transition time and half-lifetime) for monitoring the Foam decay, while Foam film Stability was measured in terms of the critical disjoining pressure of film rupture. We attempt to explain correlations between the macroscopic properties of a Foam system and those of its major building blocks (Foam films and interfaces), and thus, to identify structure-property relationships in Foam. Good correlations were found between the stabilities of black Foam films and Foams, while relations to the properties of adsorption layers appeared to be intricate. That is because pH-dependent interfacial properties of proteins usually exhibit an extremum around the isoelectric point (pI), but the Stability of BLG Foam films increases with increasing pH (3–7), which is well reflected in the Foam Stability. We discuss the possible reasons behind these intriguingly different behaviors on the basis of pH-induced changes in the molecular properties of BLG, which seem to be determining the mechanism of film rupture at the critical disjoining pressure.

  • Stability of Foam films of oppositely charged polyelectrolyte surfactant mixtures effect of isoelectric point
    Journal of Physical Chemistry B, 2011
    Co-Authors: N Kristenhochrein, R Miller, Andre Laschewsky, Regine Von Klitzing
    Abstract:

    In the present paper, the influence of the surfactant concentration and the degree of charge of a polymer on Foam film properties of oppositely charged polyelectrolyte/surfactant mixtures has been investigated. To verify the assumption that the position of the isoelectric point (IEP) does not change the character of the Foam film stabilities, the position of the IEP of the polyelectrolyte/surfactant mixtures has been shifted in two different ways. Within the first series of experiments, the Foam film properties were studied using a fixed surfactant concentration of 3 × 10(-5) M in the mixture. Due to the low surfactant concentration, this is a rather dilute system. In the second approach, a copolymer of nonionic and ionic monomer units was used to lower the charge density of the polymer. This gave rise to additional interactions between the polyelectrolyte and the surfactant, which makes the description of the Foam film behavior more complex. In both systems, the same characteristics of the Foam film stabilities were found: The Foam film Stability is reduced toward the IEP of the system, followed by a destabilization around the IEP. At polyelectrolyte concentrations above the IEP, Foam films are very stable. However, the concentration range where unstable films were formed was rather broad, and the mechanisms leading to the destabilization had different origins. The results were compared with former findings on PAMPS/C(14)TAB mixtures with an IEP of 10(-4) M.

  • Stability of Foam films of oppositely charged polyelectrolyte surfactant mixtures effect of isoelectric point
    Journal of Physical Chemistry B, 2011
    Co-Authors: N Kristenhochrein, R Miller, Andre Laschewsky, Regine Von Klitzing
    Abstract:

    In the present paper, the influence of the surfactant concentration and the degree of charge of a polymer on Foam film properties of oppositely charged polyelectrolyte/surfactant mixtures has been investigated. To verify the assumption that the position of the isoelectric point (IEP) does not change the character of the Foam film stabilities, the position of the IEP of the polyelectrolyte/surfactant mixtures has been shifted in two different ways. Within the first series of experiments, the Foam film properties were studied using a fixed surfactant concentration of 3 × 10–5 M in the mixture. Due to the low surfactant concentration, this is a rather dilute system. In the second approach, a copolymer of nonionic and ionic monomer units was used to lower the charge density of the polymer. This gave rise to additional interactions between the polyelectrolyte and the surfactant, which makes the description of the Foam film behavior more complex. In both systems, the same characteristics of the Foam film stabil...

  • Stability of Foam films and surface rheology an oscillating bubble study at low frequencies
    Journal of Physical Chemistry B, 2004
    Co-Authors: Cosima Stubenrauch, R Miller
    Abstract:

    The dilational surface elasticity e and the dilational surface viscosity η of the two nonionic surfactants n-dodecyl-β-d-maltoside (β-C12G2) and tetraethyleneglycol-monodecyl ether (C10E4) were studied using the oscillating drop method. The experiments were carried out at different concentrations and frequencies with an accessible frequency range of 0.005−0.2 Hz. The results are discussed in the light of previous disjoining pressure measurements that demonstrated that the Stability of thin liquid films cannot be explained solely by the magnitude of the surface forces. Indeed, a comparison of the results obtained for β-C12G2 with those obtained for C10E4 reveals a correlation between the Stability of the films and the surface dilational elasticity of the respective monolayers.

N Kristenhochrein - One of the best experts on this subject based on the ideXlab platform.

  • Stability of Foam films of oppositely charged polyelectrolyte surfactant mixtures effect of isoelectric point
    Journal of Physical Chemistry B, 2011
    Co-Authors: N Kristenhochrein, R Miller, Andre Laschewsky, Regine Von Klitzing
    Abstract:

    In the present paper, the influence of the surfactant concentration and the degree of charge of a polymer on Foam film properties of oppositely charged polyelectrolyte/surfactant mixtures has been investigated. To verify the assumption that the position of the isoelectric point (IEP) does not change the character of the Foam film stabilities, the position of the IEP of the polyelectrolyte/surfactant mixtures has been shifted in two different ways. Within the first series of experiments, the Foam film properties were studied using a fixed surfactant concentration of 3 × 10–5 M in the mixture. Due to the low surfactant concentration, this is a rather dilute system. In the second approach, a copolymer of nonionic and ionic monomer units was used to lower the charge density of the polymer. This gave rise to additional interactions between the polyelectrolyte and the surfactant, which makes the description of the Foam film behavior more complex. In both systems, the same characteristics of the Foam film stabil...

  • Stability of Foam films of oppositely charged polyelectrolyte surfactant mixtures effect of isoelectric point
    Journal of Physical Chemistry B, 2011
    Co-Authors: N Kristenhochrein, R Miller, Andre Laschewsky, Regine Von Klitzing
    Abstract:

    In the present paper, the influence of the surfactant concentration and the degree of charge of a polymer on Foam film properties of oppositely charged polyelectrolyte/surfactant mixtures has been investigated. To verify the assumption that the position of the isoelectric point (IEP) does not change the character of the Foam film stabilities, the position of the IEP of the polyelectrolyte/surfactant mixtures has been shifted in two different ways. Within the first series of experiments, the Foam film properties were studied using a fixed surfactant concentration of 3 × 10(-5) M in the mixture. Due to the low surfactant concentration, this is a rather dilute system. In the second approach, a copolymer of nonionic and ionic monomer units was used to lower the charge density of the polymer. This gave rise to additional interactions between the polyelectrolyte and the surfactant, which makes the description of the Foam film behavior more complex. In both systems, the same characteristics of the Foam film stabilities were found: The Foam film Stability is reduced toward the IEP of the system, followed by a destabilization around the IEP. At polyelectrolyte concentrations above the IEP, Foam films are very stable. However, the concentration range where unstable films were formed was rather broad, and the mechanisms leading to the destabilization had different origins. The results were compared with former findings on PAMPS/C(14)TAB mixtures with an IEP of 10(-4) M.

Nima Shokri - One of the best experts on this subject based on the ideXlab platform.

  • Foam Stability influenced by displaced fluids and by pore size of porous media
    Industrial & Engineering Chemistry Research, 2019
    Co-Authors: Mohammad Javad Shojaei, Kofi Oseibonsu, Paul Grassia, Simon Richman, Nima Shokri
    Abstract:

    Stability of Foam in the presence of hydrocarbons is a crucial factor in the success of its use in various applications in porous media, such as soil remediation and enhanced oil recovery (EOR). It...

  • relationship between bulk Foam Stability surfactant formulation and oil displacement efficiency in porous media
    Fuel, 2017
    Co-Authors: Kofi Oseibonsu, Paul Grassia, Nima Shokri
    Abstract:

    Success of Foam as a displacing fluid in porous media depends on longevity of Foams in the presence of non-aqueous phase liquids such as hydrocarbons. The Stability of Foam at bulk scale has been used in many cases to screen potential surfactants for core flooding studies. Although this method may aid in determining the Foamability and Stability of a surfactant, no reliable correlation has been found to exist between bulk Foam Stability and performance in porous media. We have conducted a comprehensive series of experiments to examine and compare the Stability of selected surfactant Foams at bulk scale and during oil displacement in porous media. The oil displacement was investigated in a micromodel manufactured by 3D printing technology. Our results demonstrated that oil displacement efficiency by Foam is strongly influenced by the surfactant formulation. More importantly, no meaningful correlation between the bulk Foam Stability and the oil displacement efficiency of the corresponding Foams in porous media was observed. Our pore-scale investigation shows that the Stability or inStability of Foam at bulk scale does not necessarily determine its effectiveness in porous media. Hence, performing displacement tests as presented in our study may give more insights into the potential performance of Foams.

Andre Laschewsky - One of the best experts on this subject based on the ideXlab platform.

  • Stability of Foam films of oppositely charged polyelectrolyte surfactant mixtures effect of isoelectric point
    Journal of Physical Chemistry B, 2011
    Co-Authors: N Kristenhochrein, R Miller, Andre Laschewsky, Regine Von Klitzing
    Abstract:

    In the present paper, the influence of the surfactant concentration and the degree of charge of a polymer on Foam film properties of oppositely charged polyelectrolyte/surfactant mixtures has been investigated. To verify the assumption that the position of the isoelectric point (IEP) does not change the character of the Foam film stabilities, the position of the IEP of the polyelectrolyte/surfactant mixtures has been shifted in two different ways. Within the first series of experiments, the Foam film properties were studied using a fixed surfactant concentration of 3 × 10–5 M in the mixture. Due to the low surfactant concentration, this is a rather dilute system. In the second approach, a copolymer of nonionic and ionic monomer units was used to lower the charge density of the polymer. This gave rise to additional interactions between the polyelectrolyte and the surfactant, which makes the description of the Foam film behavior more complex. In both systems, the same characteristics of the Foam film stabil...

  • Stability of Foam films of oppositely charged polyelectrolyte surfactant mixtures effect of isoelectric point
    Journal of Physical Chemistry B, 2011
    Co-Authors: N Kristenhochrein, R Miller, Andre Laschewsky, Regine Von Klitzing
    Abstract:

    In the present paper, the influence of the surfactant concentration and the degree of charge of a polymer on Foam film properties of oppositely charged polyelectrolyte/surfactant mixtures has been investigated. To verify the assumption that the position of the isoelectric point (IEP) does not change the character of the Foam film stabilities, the position of the IEP of the polyelectrolyte/surfactant mixtures has been shifted in two different ways. Within the first series of experiments, the Foam film properties were studied using a fixed surfactant concentration of 3 × 10(-5) M in the mixture. Due to the low surfactant concentration, this is a rather dilute system. In the second approach, a copolymer of nonionic and ionic monomer units was used to lower the charge density of the polymer. This gave rise to additional interactions between the polyelectrolyte and the surfactant, which makes the description of the Foam film behavior more complex. In both systems, the same characteristics of the Foam film stabilities were found: The Foam film Stability is reduced toward the IEP of the system, followed by a destabilization around the IEP. At polyelectrolyte concentrations above the IEP, Foam films are very stable. However, the concentration range where unstable films were formed was rather broad, and the mechanisms leading to the destabilization had different origins. The results were compared with former findings on PAMPS/C(14)TAB mixtures with an IEP of 10(-4) M.