Micelle soap-like

Detergents are substances including soaps that cleanse by micellar action A large number of synthetic detergents are known One example is sodium lauryl sulfate Sodium lauryl sulfate has a long hydrocarbon chain terminating m a polar sulfate ion and forms soap like micelles m water... 

These different casein monomers combine with calcium phosphate to form discrete particles on the nano-size scale. The phosphoserines of the caseins are seemingly clustered for the purpose of linking within the micelle to putative calcium phosphate microcrystallites, also known as nanoclusters (Holt, 1992 Home, 1998, 2002, 2003, 2006 Holt et al., 2003 Home et al., 2007). Structural evidence for the existence of such nanoclusters has come from neutron and X-ray scattering (de Kruif and Holt, 2003 Holt et al., 2003 Pignon et al., 2004 Marchin et al., 2007). The presence of nanoclusters allows native casein micelles to be effective natural suppliers of essential calcium salts in the human diet in a readily assimilated functional form. Protein-nanocluster interactions are the central concept of the cross-linking mechanism in Holt s model of casein micellar assembly (Holt et al., 2003 de Kruif and Holt, 2003). Any analogy with conventional soap-like micelles is considered to be... 

An interesting class of polyeleclrolytes, denoted by polysoaps, is obtained by attaching soap-like molecules to the polymer chain. Such a polysoap is for instance produced by the quaternization of polyvinyl-pyridine with /r-dodecyl bromide. The polysoap molecules differ from ordinary poly electrolytes in that they may reach protein-like compactness in solution. They behave like prefabricated soap micelles and solubilize hydrocarbons and other compounds insoluble in water,... 

Like phosphatidic acids, lecithins and cephalins contain a polar head and two long, nonpolar hydrocarbon tails. This soap-like structure gives phospholipids some interesting properties. Like soaps, they form micelles and other aggregations with their polar heads on the outside and their nonpolar tails protected on the inside. 

Liquid soap helps to reduce surface tension (Box 25.1) and therefore improves the penetration of active agents. It also improves maceration under an occlusive dressing. Anionic and cationic soaps, like alcohol, enhance the action of phe-nol. " Formulation requirements are strict. If there is too much surfactant, the phenol ends up within a micelle and its action is reduced. If there is not enough, the solutions are not stable. 

Soap-like free radical enters micelles... 

Problem 6.37 In the model for emulsion polymerization it is assumed that most of the soap-like free radicals produced in the aqueous phase enters the micelles rather than the emulsified monomer droplets. How would you justify this assumption ... 

Red wine contains a surfactant that cleanses your mouth, removing fat deposits, re-exposing your taste buds, and allowing you to savor the next bite of red meat almost as well as the first bite. The tannic acid (also called tannin) in red wine provides a soap-like action. Like soap, tannic acid consists of both a nonpolar complex hydrocarbon part as well as a polar one. The polar part of tannic acid dissolves in polar saliva, while the nonpolar part dissolves in the fat film that coats your palate. When you sip red wine, a suspension of micelles forms in the saliva. This micelle emulsion has the fat molecules in its interior the fat is washed away by swallowing the red wine. 

The formation of micelles and their properties are responsible for the cleansing action of soaps Water that contains sodium stearate removes grease by enclosing it m the hydrocarbon like interior of the micelles The grease is washed away with the water not because it dissolves m the water but because it dissolves m the micelles that are dis persed m the water Sodium stearate is an example of a soap sodium and potassium salts of other C12-C1S unbranched carboxylic acids possess similar properties... 

Phospholipids are found widely in both plant and animal tissues and make up approximately 50% to 60% of cell membranes. Because they are like soaps in having a long, nonpolar hydrocarbon tail bound to a polar ionic head, phospholipids in the cell membrane organize into a lipid bilayer about 5.0 nm (50 A) thick. As shown in Figure 27.2, the nonpolar tails aggregate in the center of the bilayer in much the same way that soap tails aggregate in the center of a micelle. This bilayer serves as an effective barrier to the passage of water, ions, and other components into and out of cells. 

We call the centre of the concentration range the critical micelle concentration (CMC). As an over-simplification, we say the solution has no colloidal micelles below the CMC, but effectively all the monomer exists as micelles above the CMC. As no micelles exist below the CMC, a solution of monomer is clear - like the solution of dilute soap in the bath. But above the CMC, micelles form in solution and impart a turbid aspect owing to Tyndall light scattering. This latter situation corresponds to washing the face in a sink. 

After leaving the plate, the grease particle remains encapsulated within the micelle, surrounded with the oil-like hydrocarbon chains of the soap monomers. The soap cleans the plate by allowing the grease to enter solution. 

By covalent linkage of different types of molecules it is possible to obtain materials with novel properties that are different from those of the parent compounds. Examples of such materials are block-copolymers, soaps, or lipids which can self-assemble into periodic geometries with long-range order. Due to their amphiphilic character, these molecules tend to micellize and to phase-separate on the nanometer scale. By this self-assembly process the fabrication of new na-noscopic devices is possible, such as the micellization of diblock-co-polymers for the organization of nanometer-sized particles of metals or semiconductors [72 - 74]. The micelle formation is a dynamic process, which depends on a number of factors like solvent, temperature, and concentration. Synthesis of micelles which are independent of all of these factors via appropriately functionalized dendrimers which form unimolecular micelles is a straightforward strategy. In... 

Soap works because the nonpolar end dissolves in dirt (oil), leaving the polar end outside the dirt. This combination is known as a micelle (see Figure 16-30). To the surrounding water molecules, the micelle appears as a very large ion. These ions tire water-soluble and repel each other due to their like charges, a behavior that causes them to remain separated. Metal ions in hcird water (Ca VMg VFe ) cause a precipitate to form because they react with carboxylate ions to form an insoluble material (also known as the soap scum hanging around the bathtub or shower). 

The experimental verification of Gibbs theorem. Since the osmotic pressure of a solution is generally difficult to measure, it is simplest to choose a case such that Raoult s law holds good and the concentration of the solution may be used in place of osmotic pressure. The solution should therefore be dilute and should be a true solution the solute, that is, must be dispersed as simple molecules and not as molecular aggregates like soap micelles. These conditions were obtained by Donnan and Barker Proc. 

Figure9.8 The absorbance of 1.05 x 10 M pinacyanol chloride at 610.0 min pH 9.59 sodium borate buffer (I = 0.1) at 50 °C vs. dodecanoate concentration. The absorption spectrum of pinacyanol chloride in aqueous solution of anionic soaps changes sharply to one characteristic of its solutions in organic solvents within a small range of soap concentration (X ax 610 nm). This effect is attributed to the formation of micelles, in whose hydrocarbon-like layers or cores the dye is solubilized. The concentration of soap at which this spectral change occurs is taken as the cmc. The use of dyes for the determination of cmc values may lead to micelle formation at a concentration below the true cmc. In practice, the method gives only a rough approximation of the cmc. (Adapted, with some modifications, from Corrin et al., 1946.)...

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