micelle

mi·celle

M0268200 (mī-sĕl′)n.1. A submicroscopic aggregation of molecules, as a droplet in a colloidal system.2. An organic particle of colloidal size found in coal.3. A coherent strand or structure in natural or synthetic fibers.

[New Latin mīcella, from Latin mīca, grain.]

mi·cel′lar (-sĕl′ər) adj.

micelle

(mɪˈsɛl) or

micell

;

micella

(mɪˈsɛlə) n (Chemistry) chem a. a charged aggregate of molecules of colloidal size in a solutionb. any molecular aggregate of colloidal size, such as a particle found in coal[C19: from New Latin micella, diminutive of Latin mīca crumb] miˈcellar adj

mi•celle

(mɪˈsɛl)

n. 1. an electrically charged colloidal particle formed by an aggregate of molecules. 2. an organized structural unit composed of such particles. [1880–85; < German Micell (1877) < Latin mīc(a) crumb, grain + -ella -elle] mi•cel′lar, adj.

Thesaurus

Noun

micelle - an electrically charged particle built up from polymeric molecules or ions and occurring in certain colloidal electrolytic solutions like soaps and detergentssubatomic particle, particle - a body having finite mass and internal structure but negligible dimensions

Translations

Micelle

enUK

micelle

[mī′sel] (cell and molecular biology) A submicroscopic structural unit of protoplasm built up from polymeric molecules. (physical chemistry) A colloidal aggregate of a unique number (between 50 and 100) of amphipathic molecules, which occurs at a well-defined concentration known as the critical micelle concentration.

Micelle

a particle of the disperse phase of a sol, that is, of a highly disperse colloidal system with a liquid dispersion medium.

Micelles consist of nuclei of crystalline or amorphous structure and of a surface layer containing solvated molecules of the liquid medium. The surface layer of a micelle of a lyophilic sol is formed of adsorbed molecules or ions of a stabilizer. In the case of lyophobic hydrosols stabilized by electrolytes, the nucleus of the micelle is surrounded by two layers of oppositely charged ions (the electric double layer). There is an equal number of positive and negative charges in the electric double layer; the micelle as a whole is therefore electrically neutral.

The ions of the adsorption layer are located directly on the surface of the nucleus. All ions of one of the signs and some of those of the opposite sign (counterions) are part of this layer. The remainder of the counterions form the diffuse layer, which surrounds the micelle as an ionic cloud whose density decreases with increasing distance from the nucleus. The diffuse layer hinders the approach and aggregation (cohesion) of particles in Brownian motion.

In lyophilic sols and colloidal dispersions of the soap hydrosol type (for example, of sodium oleate or potassium lauryl sulfate), the micelles are molecular aggregates. In each molecule a long hydrocarbon (hydrophobic) chain is bound to a polar (hydrophilic) group. In forming the micelle, dozens or even hundreds of molecules aggregate, so that the hydrophobic radicals form the nucleus (inner region) and the hydrophilic groups form the surface layer. If the dispersion medium is an organic liquid, the orientation of the molecules in the micelle may be reversed. The polar groups concentrate in the nucleus, and the hydrophobic radicals are directed toward the external phase.

The simplest structural types of micelles may be diagramed with the micelle-forming molecule represented as a wavy line (hydrophobic chain) with a small circle (hydrophilic group) at the end (see Figure 1).

Figure 1. Basic micelle types

Micelle structures (1) and (2) represent hydrophilic sols; types (3) and (4), organophilic sols. Upon dilution of the system below the critical micelle-formation concentration, spherical micelles (1) and (3) decompose reversibly into separate molecules or dimers. At higher concentrations, they are converted into lamellar micelles, represented by types (2) and (4); these may interact to form a structural gel network within the system.

The detergent action of aqueous solutions (more precisely, of colloidal dispersions) of soaps, as well as certain phenomena in biological systems and technological processes, are explained by the presence of micelles.

L. A. SHITS

micelle

[mi-sel´] a supermolecular colloid particle, most often a packet of chain molecules in parallel arrangement.

mi·celle

(mi-sel', mī-sel'), 1. Nägeli term for elongated sub(light)microscopic particles, detected in hydrogels, of supramolecular character and crystalline structure; now defined as one of two classes of colloidal particle: those consisting of many molecules, the other class being single macromolecules light- or submicroscopic in size. A micelle is thus a structural unit of the disperse phase in a gel, a unit whose repetition in three dimensions constitutes the micellar structure of the gel; it does not denote the individual particles in free suspension or solution, or the unit structure of a crystal. 2. Any water-soluble aggregate, spontaneously and reversibly, formed from amphiphile molecules. 3. A hypothetical ordered region in a natural fiber such as cellulose. [L. micella, small morsel, dim. of mica, morsel, grain]

micelle

(mī-sĕl′)n. A submicroscopic aggregation of molecules, as a droplet in a colloidal system.

mi·cel′lar (-sĕl′ər) adj.

micelle

Chemistry
An organised component of colloidal suspensions, consisting of spherical or laminar aggregates of polar surface-active molecules (soaps). The hydrophilic portion of the molecule interacts with the other members of the aqueous solution (i.e., are oriented outside in water); the hydrophobic ends huddle together within the micelle.
Micelles of the small intestine are composed of bile salts with fatty acids and monoglycerides released by pancreatic lipase.

Molecular biology
The structure formed by amphipathic molecules in solution, which places the polar group toward the solution and the hydrophobic group toward the interior.

micelle

a cluster of phospholipid molecules in the gut which are dispersed by the action of BILE salts.

mi·celle

(mi-sel') 1. Elongated sub(light)microscopic particles, detected in hydrogels, of supramolecular character and crystalline structure. 2. Any water-soluble aggregate, spontaneously and reversibly, formed from amphiphile molecules. 3. A hypothetical ordered region in a natural fiber such as cellulose. [L. micella, small morsel, dim. of mica, morsel, grain]

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Words related to micelle

noun an electrically charged particle built up from polymeric molecules or ions and occurring in certain colloidal electrolytic solutions like soaps and detergents

Related Words