Hydrophobic groups polar group hydration

The classical model, as shown in Figure 1, assumes that the micelle adopts a spherical structure [2, 15-17], In aqueous solution the hydrocarbon chains or the hydrophobic part of the surfactants from the core of the micelle, while the ionic or polar groups face toward the exterior of the same, and together with a certain amount of counterions form what is known as the Stern layer. The remainder of the counterions, which are more or less associated with the micelle, make up the Gouy-Chapman layer. For the nonionic polyoxyethylene surfactants the structure is essentially the same except that the external region does not contain counterions but rather rings of hydrated polyoxyethylene chains. A micelle of... 

Figure 6.8 Sketch of proposed molecular mechanism of protein-surfactant interaction for CITREM + sodium caseinate (0.5 % w/v in aqueous medium (pH = 7.2, ionic strength = 0.05 M) at 293 K. Picture (I) shows the water molecules bound with polar groups of the protein and surfactant, as w ell as w ater molecules structured as a result of hydrophobic hydration around the hydrocarbon chain of the surfactant. (For clarity, the free w ater molecules are not shown.) Picture (H) demonstrates the release of bound and structured water molecules resulting Rom the predominantly hydrophobic interactions between protein and surfactant. Reproduced Rom Semenova et al. (2006) with permission.

The effect of low concentrations of urea (2M) on the large dihydroxy bile salt micelles is striking, while similar concentrations have no effect on the small trihydroxy or dihydroxy micelles. The effects of urea on micelle formation and aggregate size are undoubtedly complicated (10) and involve changes in solvent structure and thus hydrophobic bonding and hydration of polar groups. For large micelles of dihydroxy bile salt... 

Hydrophobic and hydrophilic are categories of hydration effects in aqueous liquids. Classical ions such as Na+ or polar molecules such as urea [(NH2)2 CO] are simply recognized hydrophihc solutes. In contrast, the interactions of hydrophobic solutes or groups with water molecules do not display classic electrostatic... 

To summarize, three conclusions transpire from the nanoscale thermodynamics results (a) The interfacial tension between protein and water is patchy and the result of both nanoscale confinement of interfacial water and local redshifts in dielectric relaxation (b) the poor hydration of polar groups (a curvature-dependent phenomenon) generates interfacial tension, a property previously attributed only to hydrophobic patches and (c) because of its higher occurrence at protein-water interfaces, the poorly hydrated dehydrons become collectively bigger contributors to the interfacial tension than the rarer nonpolar patches on the protein surface. 

The POPs we consider in this chapter are non-ionizable, and largely non-polar. These characteristics make them poorly soluble in water and thus hydrophobic. Introduction of an ionizable functional group, such as a sulfate or conjugate as occurs with metabolism, greatly increases the water solubility of hydrophobic compounds (due to hydration of the ionizable moieties), and such modified compounds are rapidly... 

I.2. Hydrophilic-hydrophobic factor and criteria Hydrophilic characteristics of a reagent molecule include hydration tendency of the polar head itself and hydrophilicity of the reagent-metal bond at the mineral surface. The characteristics of the non-polar group of a reagent determine its use. The criteria of hydrophilic-hydrophobic factors affecting the structure property relationship of the reagent include characteristic index i and hydrophilic-hydrophobic balance (HHB). 

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