Ternary surfactant-hydrocarbon-water

Solid soils are commonly encountered in hard surface cleaning and continue to become more important in home laundry conditions as wash temperatures decrease. The detergency process is complicated in the case of solid oily soils by the nature of the interfacial interactions of the surfactant solution and the solid soil. An initial soil softening or "liquefaction", due to penetration of surfactant and water molecules was proposed, based on gravimetric data (4). In our initial reports of the application of FT-IR to the study of solid soil detergency, we also found evidence of rapid surfactant penetration, which was correlated with successful detergency (5). In this chapter, we examine the detergency performance of several nonionic surfactants as a function of temperature and type of hydrocarbon "model soil". Performance characteristics are related to the interfacial phase behavior of the ternary surfactant -hydrocarbon - water system. 

Raney K, Benton W, Miller CA (1987) Optimum detergency conditions with nonionic sm-factants I. Ternary water-surfactant-hydrocarbon system. J Colloid Interface Sci 117 282-290... 

Raney, K.H., Benton, W.J., and Miller, C.A., Optimum detergency conditions with nonionic surfactants I. Ternary water-surfactant-hydrocarbon systems, J. Colloid Interface Sci., 117, 282, 1987. 

Many surfactant solutions are known which contain spherical micelles up to high surfactant concentrations and behave as Newtonian liquids with a low viscosity. This is especially the case for ternary systems of surfactant, hydrocarbon and water where the spheres are stabilized by the solubilization of the non-polar hydrocarbon. 

For a large variety of amphiphilic compoimds cubic phases are a particular class of surfactant systems normally observed in the more concentrated region of the phase diagram [53]. Such phases may occur in binary systems (surfactant and water) as well as in ternary or pseudo ternary systems, where usually a hydrocarbon is the third component. In addition they may contain a long alcohol chain as a fourth component (cosurfactant). Such a composition reminds one of that of microemulsions and for that reason they are also called microemulsion gels [54]. However, the denomination cubic phase is insofar more instructive since it relates directly to the structure of the corresponding systems. 

Ternary systems consisting of surfactant, hydrocarbon and water exhibit a rich variety of phases. With increasing fraction of the hydrophobic components, frequently a sequence of structural changes of the type... 

According to Shinoda and Kunieda [111], aqueous microemulsions can form from ternary mixtures of a hydrocarbon, a nonionic surfactant, and water when the temperature of the system is kept between the solubilization temperature (lower limit) and the cloud point (higher limit). The area between the solubiliza-... 

The hybrid surfactants synthesized by Guo et al. [206] hydrolyze in moist air and have to be stored in a desiccator. Yoshino et al. [207] synthesized hybrid surfactants which contain an aromatic ring C F2 +iC6H4C0CH(S03Na)-C, H2w+i, where n = 4 and 6, m = 2. 4, and 6, and C6H4 = p-phenylene. These surfactants are stable in the presence of moisture and can emulsify a ternary system consisting of mutually immiscible components hydrocarbon, water, and per-fluoroether oil. 

Within a simple ternary DDAB-water-hydrocarbon system, it is reasonable to expect that the effective surfactant parameter remains approximately constant throughout the triangular phase diagram, just as it does along the upper water limit. (Note however, that the head-group area can change at low water fractions due to the effects of hydration on the polar head.)... 

Figure 4.20 Artist s impressiort of the interfadal geometry of a ternary microemulsion made up of a double-chain cationic surfactant "dissolved" in a mixture of water and short chain hydrocarbons. The cormectivity of the surfactant interface - which encloses the water network -decreases as water is added to the mixture (left average coordination number of four right average coordination munber of two).

In the preceding sections, the phase behaviour of rather simple ternary and quaternary non-ionic microemulsions have been discussed. However, the first microemulsion found by Schulman more than 50 years ago was made of water, benzene, hexanol and the ionic-surfactant potassium oleate [1, 3]. Winsor also used the ionic-surfactant sodium decylsulphate and the co-surfactant octanol to micro-emulsify water/sodium sulphate and petrol ether [2], In the last 30 years, in-depth studies on ionic microemulsions have been carried out [7, 8, 65, 66]. It toned out that nearly all ionic surfactants which contain one single hydrocarbon chain are too hydrophilic to build up microemulsions. Such systems can only be driven through the phase inversion if an electrolyte and a co-surfactant is added to the mixture (see below and Fig. 1.11). 

Figure 17 Illustration of the fact that microemulsion structure is not simply a function of composition. Shown are partial ternary phase diagrams with nonionic and cationic surfactants at room temperature. For a similar composition (approximately 15% surfactant, 65 wt% water, and 20 wt% oil), the microstructures of the two systems are widely different, as shown by the ratio of the water and oil diffusion coefficients, Dn /Dhc where he here denotes oil (hydrocarbon). The nonionic system has an oil-in-water structure (D //)hc = 200), while the cationic system has a water-in-oil structure (D,/Z)h. = 1/200).

Figure 5 illustrates the conventional diagram normally used for oil-water-alcohol (or surfactant) processes. For CO2 or hydrocarbon-miscible processes, authors conventionally rotate the ternary diagram 120° clockwise, but the illustrated principle is the same. The binodal curve is normally higher for alcohol and lower for surfactants than the curve shown in Figure 5. Although no real reservoir process can be completely miscible in the exact...

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