Interfacial tension emulsification affected

The negatively charged hydrophilic headgroup of the anionic surfactants may comprise sulfate, sulfonate, sulfosuccinate or phosphate groups attached to an extended hydrophobic backbone [82]. The nature of the hydrophilic group will influence the extent of electrostatic stabilization, the behaviour of the surfactant as a fiinction of pH, the degree of hydrolysis, and the variation of latex stability with time, electrolyte and temperature conditions. The nature of the backbone hydrophobe will influence the adsorption behaviour of the surfactant onto the latex particle surface, its cmc value, the interfacial tension (which affects monomer emulsification), and the extent of steric stabilization, among other factors. 

Several mechanisms have been identified that aid oil recovery in the alkaline process. These include the following lowering of interfacial tension, emulsification of oil, and wettability changes in the roekfoimation. All three mechanisms can affect the microseopie displacement efficiency, and emulsification can also affect the macroscopic displacement efficiency. If a wettabiUty change is desired, a high (2.0-5.0 wt %) eoneentration of alkahne should be used. Otherwise, concentrations of the order of 0.5-2.0 wt % of alkaline are used. 

Sodium lauryl sulfate is often used in medicinal preparations. As mentioned above, it is used as an emulsifer for creams and lotions in cosmetic preparations, but due to its low toxicity and biological compatibility it is also used in the preparation of creams, gels, and emulsions in which the medications are dispersed. Its ability to lower the interfacial tension affects the potentiation and availability of medications. 

Emulsification is a stabilizing effect of proteins a lowering of the interfacial tension between immiscible components that allow the formation of a protective layer around oil droplets. The inherent properties of proteins or their molecular conformation, denaturation, aggregation, pH solubility, and susceptibility to divalent cations affect their performance in model and commercial emulsion systems. Emulsion capacity profiles of proteins closely resemble protein solubility curves and thus the factors that influence solubility properties (protein composition and structure, methods and conditions of extraction, processing, and storage) or treatments used to modify protein character also influence emulsifying properties. 

The presence of a surfactant means that, during emulsification, the interfacial tension need not to be the same everywhere (see Figure 10.17). This has two consequences (i) the equilibrium shape of the drop is affected and (ii) any... 

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