High surface charge density

Due to the finite size of the ions and the solvent molecules, the solution shows considerable structure at the interface, which is not accounted for in the simple Gouy-Chapman theory. The occurrence of a decrease of C from the maximum near the pzc is caused by dielectric saturation, which lowers the dielectric constant and hence the capacity for high surface-charge densities. 

Cationic PNIPAM/ PS core-shell particles Two-steps protocol 1) batch EFEP of styrene and NIPAM 2) shot-growth a of MBA NIPAM, AEMH 300-600 nm High surface charge density. Variable hairy layer thickness [16,17]... 

Equation (6.6) cannot be solved analytically but its approximate solution for the case of dilute suspensions has been obtained by Imai and Oosawa [3,4]. They showed that there are two distinct cases separated by a certain critical value of the surface charge density cr or the total surface charge Q, that is, case 1 low surface charge density case and case 2 high surface charge density case, as schematically shown in Fig. 6.2. For case 1, there are two regions I R [Pg.135]

We compare the exact numerical solution to the Poisson-Boltzmann equation (6.6) and the approximate results, Eq. (6.37) for case 1 (low surface charge density case) and Eq. (6.50) for case 2 (high surface charge density case) in Fig. 6.3, in which the scaled surface potential jo = zeij/JkT is plotted as a function of the scaled... 

Low hydrated surface High surface charge density High adsorption... 

Figure 1.4. Formation of R+ species ([Pt(T 3-allyl)P(C6H5)3]+) from [Pt(r 3-allyl) XP(C6Hs)3] complexes, due to the formation of an ion pair catalyzed by the high surface charge density present in the droplet.

Davies (16) applied both equations to a wide collection of data at fairly low A for both soluble and insoluble ionized species and achieved only limited agreement between theory and experiment for some mono-layers. Nevertheless, the Davies term is the basis of nearly every subsequent discussion on the isotherms of ionized monolayers. We discuss elsewhere (25, 26) the validity of Equations 7 and 8 for intermediate and high surface charge densities as well as other proposed equations of state (14, 27, 28, 29, 30, 31, 32). In this paper we establish whether these two equations are suitable limiting forms at high A where many of the assumptions used in their derivation should be more valid. In particular we are interested in the limit of UA at zero n for both interfaces. 

The metals of the s block of the Periodic Table have properties that can be interpreted in terms of the trend in their ionic radii down each periodic column. There is a very strong tendency towards formation of M+ (for ns1 or alkali) and M2+ (for ns2 or alkaline earth) metal ions, and other oxidation states are not important. With relatively high surface charge density, the alkali and alkaline earth metal ions are hard Lewis acids and have a preference for small hard Lewis bases. They particularly like O-donors, but can also accommodate N-donors, especially when present as part of a molecule offering a mixed 0,N-donor set. The number of metal-donor bonding interactions varies a great deal, depending in one... 

Metal ions of +3 oxidation state have a high surface charge density and consequently solvent molecules are tightly held. Resulting from this is the strong tendency for hydrolysis to take place according to an acid—base equilibrium of the type... 

A popular representation of spherical micelles was devised by Hartley (26). As indicated in Fig. 1, the Hartley model of, e.g., an anionic micelle exhibits a spherical electric double layer composed of bulky, hydrated anionic heads of surfactant molecules and their counterions in the aqueous phase, while the hydrophobic tails, visualized as sticks, form a hydrocarbon-like micellar interior. Because of the high surface charge density of the micelle, there is only little electrolytic dissociation of counterions. The Hartley model explains the low conductivity of micellar solutions and the way surfactants work as detergents by solubilizing (i.e. incorporating) hydroi obic substrates. The model fails to explain certain NMR and fluorescence data that demonstrate some contact of... 

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