Multiple emulsion definition

An emulsion is a heterogeneous system, consisting of at least one immiscible liquid intimately dispersed in another in the form of droplets, whose diameter, in general, exceeds 0.1 micron (italics ours) . He has further opined that such systems possess a minimal stability, which may be accentuated by such additives as surface active agents, finely divided solids etc. [1]. The presence of a surface active agent (see below, and also Chapter 2) obviously makes the system tri-component. More recently, Dickinson [2] accepted the traditional definition of an emulsion as an opaque, heterogeneous system of two immiscible liquid phases ( oil and water ) with one of the phases dispersed in the other as droplets of microscopic or colloidal size . In spite of Becher s contention that the dispersed phase is a liquid, it has been commented that the difference between a liquid-in-liquid emulsion and a solid particle dispersion in a liquid is not entirely distinct [2]. Further, in an emulsion, the dispersed phase itself can be an emulsion, so that this multiple emulsion can be of the types water-in-oil-in water or oil-in-water-in-oil [3,4]. We can also have more than one dispersed phase in a continuous phase, e.g. two kinds of aqueous solution in oil for very short periods before collision and coalescence, which is a very important route for synthetic reactions. Examples of the varieties of emulsions relevant to solid particle preparation will be cited and discussed in later Chapters. 

A type of processing equipment in which the entire amount of material to be used is put into the mixer and mixed for a definite period, with multiple recirculation of material through the mixing zone, in contrast to what happens in a continuous mixer. After the mixing period the whole amount of material is removed from the mixer. In oil production or processing, the process in which emulsion is collected in a tank and then broken in a batch. This process is used as opposed to continuous or flow-line treating of emulsions. 

---