High-energy emulsification methods

II. NANO-EMULSION FORMATION A. High-Energy Emulsification Methods... 

As mentioned in introduction, nano-emulsions being nonequilibrium systems require an energy input for their formation, which can be supplied mechanically (high-energy emulsification), or from the chemical energy of the components (condensation or low-energy emulsification methods). In this section, the different condensation methods, which are classified as self-emulsification and phase inversion methods, will be discussed. 

Many kinds of polymerizable miniemulsion recipes have been described [9,85]. In the majority of the described systems, the emulsification is achieved by high-energy methods. The emulsifier in the earlier formulations [1] consisted of ionic surfactant/fatty alcohol (cosurfactant) mixtures. It was thought that the stabilizing mechanism was due to the presence of a protective interfacial complex. Later, it was shown that the replacement of the fatty alcohol by a highly hydrophobic compound (e.g., hexadecane) decreased more effectively the Ostwald ripening without the existence of any interfacial complex [9]. Different types of molecules such as reactive co-... 

In the laboratory, very reproducible W/0 emulsions of monodispersed size distributions can be prepared when all the variables for emulsification are controlled. The variables for a beneh laboratory study are emul-sifier type and concentration, energy of mixing, time of mixing, method of mixing, volume fraetions of oil and water phases, type and viseosity of oil, quality of water, and temperature. The mixtiue is blended in specific vessels, usually with rest intervals to eontrol the rigidity of the film. The conditions are reprodueed from batch to batch. In real production this is not often the case. The immiseible phases are subject to variable high shear for 2-8 min in offshore production and 40-50 min in the oil sands extraetion process. Emulsion size distributions therefore vary with different systems. 

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