Phase behavior, aqueous surfactant

R. G. Laughlin, The Aqueous Phase Behavior of Surfactants, Academic, London, 1994. 

R Hansson and M. Akngren Interaction of Alkyltrimethylammonium Surfactants with Polyacrylate and Poly(Styrenesulfonate) in Aqueous Solution Phase Behavior and Surfactant Aggregation Numbers. Langmuir 10, 2115 (1994). 

Laughlin RG (1994) The aqueous phase behavior of surfactants. Academic, London... 

It is well known that the aqueous phase behavior of surfactants is influenced by, for example, the presence of short-chain alcohols [66,78]. These co-surfactants increase the effective value of the packing parameter [67,79] due to a decrease in the area per head group and therefore favor the formation of structures with a lower curvature. It was found that organic dyes such as thymol blue, dimidiiunbromide and methyl orange that are not soluble in pure supercritical CO2, could be conveniently solubihzed in AOT water-in-C02 reverse microemulsions with 2,2,3,3,4,4,5,5-octafluoro-l-pentanol as a co-surfactant [80]. In a recent report [81] the solubilization capacity of water in a Tx-lOO/cyclohexane/water system was foimd to be influenced by the compressed gases, which worked as a co-surfactant. 

The phase behavior of surfactant systems is particularly complex because of the existence of numerous lyotropic (solvent-induced) liquid crystal phases (3). These phases, like liquids and crystals, are discrete states of matter. They are fluids, but their x-ray patterns display sharp lines signifying the existence of considerable structure. They are often extremely viscous because of their high viscosities and for other reasons they are difficult to study using conventional methods. This is evident from the fact that serious errors in the presumably well-established classical aqueous phase diagrams of soaps, sodium alkyl sulfates, monoglycerides, and... 

Laughlin RG (1994). The Aqueous Phase Behavior of Surfactants, Academic Press, New York. Lequeux F, Candau SJ (1997). In Theoretical Challenges in the Dynamics of Complex Fluids, McLeish TCB (ed), NATO ASI Series E Applied Sciences, Vol 339, Kluwer, London, p 181. Linemann R, Lauger J, Schmidt G, Kratzat K, Richtering W (1995). Rheol Acta 34 440. 

Phase Behavior. The surfactant formulations for enhanced oil recovery consist of surfactant, alcohol and brine with or without added oil. As the alcohol and surfactant are added to equal volumes of oil and brine, the surfactant partitioning between oil and brine phases depends on the relative solubilities of the surfactant in each phase. If most of the surfactant remains in the brine phase, the system becomes two phases, and the aqueous phase consists of micelles or oil-in-water microemulsions depending upon the amount of oil solubilized. If most of the surfactant remains in the oil phase, a two-phase system is formed with reversed micelles or the water-in-oil microemulsion in equilibrium with an aqueous phase. 

A book by Laugh in [76] is a very valuable reference on the aqueous phase behavior of surfactants. It covers this vast area of science from the viewpoints of the role of phase science within physical science, physical chemistry (thermodynamics of immiscibility, phase diagrams, the phase rule, characteristic features of surfactant phase behavior, kinetic and mechanistic aspects of surfactant phase behavior, relative humidity), structures and properties of surfactant phases, molecular correlations (surfactant and nonsurfactant behavior in amphiphilic molecules, hydrophilicity, lipophilicity, proximate and remote substituent effects, influence of third components on aqueous surfactant phase behavior), the relationship of the physical science of surfactants to their utility, and the history of surfactant phase science. 

Hansson P, Almgren M. Interaction of alkyltrimethylammonium surfactants with poly(acrylate) and poly(styrenesulfonate) in aqueous solution. Phase behavior and surfactant aggregation numbers. Langmuir 1994 10 2115-2124. 

The knowledge of the phase behavior of surfactants or polymers in water or in oils is a basic understanding of the properties of these systems, and it is very important for surfactant industrial applications. It has been found that depending on the temperature or composition, the surfactants form a variety of self-assembled structures in water and oils or in both [54-63]. In comparison to the aqueous systems, the surfactant/oil systems offer less variety of self-assembled structures [9, 64—68]. In the following sections, the phase behavior of mono- and diglycerol fatty acid esters in a variety of organic oils will be described. 

Laughlin RG (1994) The Aqueous phase behavior of Surfactants. Academic Press, Harcourt Brace Company Publishers, London, San Diego, New York, Boston, Sydney, Tokyo, Toronto... 

Laughlin, R. G. 1994. Aqueous phase behavior of surfactants. New York Academic... 

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