A Comparative Study of Phase Behaviour in Aqueous Systems of Catanionic Surfactants and Ionic Surfactants with Organic Counterions

The clays of the smectite group, mainly montmorillonite, are widely used in the production of organoclays due to the small dimensions of the crystals, high cation exchange capacity (CEC), and swelling capacity in water, which lead to a rapid and efficient intercalation of organic compounds used in the synthesis. In this context, this research was intended to make a comparative study of clays organofilized with ionic surfactants through their respective CEC. We selected four samples of bentonites, namely Chocolate (Boa Vista, PB), Brasgel (industrial), Dark Bentonite (Pedra Lavrada, PB) and M400 Bentonite (industrial). The natural samples were characterized through XRD, EDX, TA and GA, and the organofilized ones through XRD. The characterization tests showed that the samples are composed of clay minerals of the smectite group, the CEC values were insignificant changes when comparing the values of natural and activated clays with sodium carbonate. And the levels indicated by the CEC for the ionic surfactant Praepagem HY proved insufficient to transform the organophilic clays, as the nominees for the ionic surfactant Praepagem WB led to adequate results regarding the incorporation of the surfactant in the clay fraction of the studied samples.

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Phase behaviour of binary mixtures of membrane polar lipids in aqueous systems

Natural Product Reports ◽

10.1039/np9870400129 ◽

1987 ◽

Vol 4 ◽

pp. 129 ◽

Cited By ~ 1

Author(s):

P. J. Quinn

Keyword(s):

Binary Mixtures ◽

Polar Lipids ◽

Phase Behaviour ◽

Aqueous Systems

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Measurement of the phase behaviour of the binary systems {carbon dioxide (CO2)+non-ionic surfactants (CiEOj)}

The Journal of Chemical Thermodynamics ◽

10.1016/j.jct.2011.09.018 ◽

2012 ◽

Vol 45 (1) ◽

pp. 109-113 ◽

Cited By ~ 4

Author(s):

Tania E. Sandoval ◽

M. Pilar Gárate

Keyword(s):

Carbon Dioxide ◽

Binary Systems ◽

Phase Behaviour ◽

Ionic Surfactants ◽

Carbon Dioxide Co2

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Direct characterization of adsorbed surfactant layers

Surfactants ◽

10.1093/oso/9780198828600.003.0008 ◽

2019 ◽

pp. 156-174

Author(s):

Bob Aveyard

Keyword(s):

Refractive Index ◽

Layer Thickness ◽

Quartz Crystal Microbalance ◽

Adsorbed Layer ◽

Phase Behaviour ◽

Aqueous Systems ◽

Brewster Angle Microscopy ◽

Physical Investigation ◽

Neutron Reflection

Some widely used techniques for the direct physical investigation of the structure of adsorbed surfactant films are introduced. Neutron reflection has yielded very detailed information about adsorbed surfactant films, although it is not readily accessible to many researchers. There are however commercial instruments available for a number of other techniques which are to be found in numerous laboratories. Scanning probe microscopies (STM and AFM) are capable of producing quite remarkable images of surfactant layers on solids and clearly show how surfactants form aggregates at surfaces. Ellipsometry is capable of yielding adsorbed layer thickness and refractive index from which composition with respect to solvent and surfactant can be deduced. The quartz crystal microbalance (QCM) and its variant, QCM-D, can give adsorbed amounts (including hydration in aqueous systems). Brewster angle microscopy (BAM) is a useful tool for the visualization of phase behaviour in surfactant films.

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