emulsion


emulsion
emulsive, adj.
/i mul"sheuhn/, n.
1. Physical Chem. any colloidal suspension of a liquid in another liquid.
2. such a suspension used in cosmetics.
3. Pharm. a liquid preparation consisting of two completely immiscible liquids, one of which, as minute globules coated by a gum or other mucilaginous substance, is dispersed throughout the other: used as a means of making a medicine palatable.
4. Photog. a composition sensitive to some or all of the actinic rays of light, consisting of one or more of the silver halides suspended in gelatin, applied in a thin layer to one surface of a film or the like.
[1605-15; < NL emulsion- (s. of emulsio), equiv. to L emuls(us) milked out (e- E- + mulsus, ptp. of mulgere to milk) + -ion- -ION]

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Mixture of two or more liquids in which one is dispersed in the other as microscopic or ultramicroscopic droplets (see colloid).

Emulsions are stabilized by agents (emulsifiers) that (e.g., in the case of soap or detergent molecules) form films at the droplets' surface or (e.g., in the case of colloidal carbon, bentonite clay, proteins, or carbohydrate polymers) impart mechanical stability. Less-stable emulsions eventually separate spontaneously into two liquid layers; more-stable ones can be destroyed by inactivating the emulsifier, by freezing, or by heating. Polymerization reactions are often carried out in emulsions. Many familiar and industrial products are oil-in-water (o/w) or water-in-oil (w/o) emulsions: milk (o/w), butter (w/o), latex paints (o/w), floor and glass waxes (o/w), and many cosmetic and personal-care preparations and medications (either type).

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 in physical chemistry, mixture of two or more liquids in which one is present as droplets, of microscopic or ultramicroscopic size, distributed throughout the other. Emulsions are formed from the component liquids either spontaneously or, more often, by mechanical means, such as agitation, provided that the liquids that are mixed have no (or a very limited) mutual solubility. Emulsions are stabilized by agents that form films at the surface of the droplets (e.g., soap molecules) or that impart to them a mechanical stability (e.g., colloidal carbon or bentonite). Unstable emulsions eventually separate into two liquid layers. Stable emulsions can be destroyed by inactivating or destroying the emulsifying agent—e.g., by adding appropriate third substances or also by freezing or heating. Some familiar emulsions are milk (a dispersion of fat droplets in an aqueous solution) and butter (a dispersion of droplets of an aqueous solution in fat).

      Emulsions are important in many fields—e.g., in the dyeing and tanning industries, in the manufacture of synthetic rubber and plastics, in the preparation of cosmetics such as shampoos, and of salves and therapeutic products.

      The term emulsion is often applied to mixed systems that should better be characterized as solutions, suspensions, or gels. For example, the so-called photographic emulsion is actually a gelatin gel in which tiny crystals (e.g., of silver bromide) are dispersed.

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Universalium. 2010.

Look at other dictionaries:

  • émulsion — [ emylsjɔ̃ ] n. f. • 1560; lat. emulsum, supin de emulgere « traire » 1 ♦ Préparation liquide d apparence laiteuse tenant en suspension une substance huileuse ou résineuse (ex. lait d amandes). 2 ♦ Chim. Mélange hétérogène de deux liquides non… …   Encyclopédie Universelle

  • Emulsión — Saltar a navegación, búsqueda A. Dos líquidos inmiscibles, fase I y fase II, no emulsificados; B. Emulsión de fase II disperso en la fase I; C. La emulsión inestable se separa progresivamente; D. Las posiciones surfactantes (borde púrpura) en las …   Wikipedia Español

  • Emulsion — Émulsion Une émulsion est un mélange homogène de deux substances liquides non miscibles (qui ne se mélangent normalement pas), comme l’eau et l’huile. Une substance est dispersée dans la seconde substance sous forme de petites gouttelettes. Le… …   Wikipédia en Français

  • Emulsion — Sf Gemenge aus zwei nicht mischbaren Flüssigkeiten; lichtempfindliche Schicht per. Wortschatz fach. (18. Jh.) Entlehnung. Neubildung zu l. ēmulsum n., dem PPP. von l. ēmulgēre ausmelken, abmelken , zu l. mulgēre melken und l. ex . So benannt nach …   Etymologisches Wörterbuch der deutschen sprache

  • emulsion — 1610s, from Fr. émulsion (16c.), from Mod.L. emulsionem (nom. emulsio), from emulsus, pp. of emulgere to milk out, from ex out (see EX (Cf. ex )) + mulgere to milk (see MILK (Cf. milk)). Milk is a classic instance …   Etymology dictionary

  • Emulsion — »Gemenge aus zwei nicht mischbaren Flüssigkeiten; lichtempfindliche Schicht«: Das Wort ist eine fachsprachliche Bildung zu lat. emulsus, dem Part. Perf. von e mulgere »aus , abmelken« (vgl. ↑ melken). Es bedeutet also eigentlich »Aus ,… …   Das Herkunftswörterbuch

  • emulsión — sustantivo femenino 1. Área: química Líquido que tiene en suspensión partículas diminutas de otra sustancia, sin llegar a formar una disolución: Este salchichón no está hecho con carne picada, sino con emulsión. 2. Área: fotografía Suspensión de… …   Diccionario Salamanca de la Lengua Española

  • emulsión — (Del lat. emulsus, ordeñado). 1. f. Fís. y Quím. Dispersión de un líquido en otro no miscible con él. La emulsión de aceite en agua. 2. Fotogr. Suspensión coloidal de bromuro de plata en gelatina que forma la capa sensible a la luz del material… …   Diccionario de la lengua española

  • emulsion — ► NOUN 1) a fine dispersion of minute droplets of one liquid in another in which it is not soluble or miscible. 2) a type of paint consisting of pigment bound in a synthetic resin which forms an emulsion with water. 3) a light sensitive coating… …   English terms dictionary

  • Emulsion — E*mul sion, n. [From L. emulgere, emulsum: cf. F. [ e]mulsion. See {Emulge}.] Any liquid preparation of a color and consistency resembling milk; as: (a) In pharmacy, an extract of seeds, or a mixture of oil and water united by a mucilaginous… …   The Collaborative International Dictionary of English

  • Emulsion — Emulsion. См. Эмульсия. (Источник: «Металлы и сплавы. Справочник.» Под редакцией Ю.П. Солнцева; НПО Профессионал , НПО Мир и семья ; Санкт Петербург, 2003 г.) …   Словарь металлургических терминов


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