Surface charge density dissociated

Intrinsic surface charge density, defined by the number of Coulombs per square meter bound by surface functional groups, either because of isomorphic substitutions, or because of dissociation/protonation reactions. 

The concentration of Na cation, resulting from the dissociation of AOT, will be neglected, since it is at least a few times lower than the concentration of the electrolyte cation. The reassociation of the AOT adsorbed on the surface with the electrolytes cations is taken into account via the association—dissociation equilibrium, which leads to a surface charge density os given by30... 

A more realistic calculation is presented in Fig. 5b, which implies that there is a surface charge density generated by the dissociation of surface groups. Assuming that the cations can be bound to N negative sites per unit area, the dissociation equilibrium provides the expression ... 

In summary, when the surface charge was generated by the dissociation equilibrium of surface groups, the surface charge density was almost constant for large dissociation constants and low surface potentials. In this case, the neglecting of the change in the chemical free... 

ILB. The Surface Charge. Denoting by a the dissociation constant, the surface charge density a is given... 

IIA. The Surface Density of Surfactant. The surface density of surfactant is relevant for both the double layer (caused by the surface charge density generated via the dissociation of the surfactant adsorbed at the interface) and the hydration interaction (caused by the ion pair density of the non-dissociated surfactant molecules). The surface density of an anionic surfactant, I, will be related to the saturation surface density, I , via the Frumkin adsorption isotherm... 

The traditional theory could not explain the above observations. In recent papers concerned with monovalent electrolytes,4,5 the restabilization was attributed to the following two effects (i) the reassociation of charges on the surface and their replacement by ion pairs (surface dipoles), and (ii) the fields generated by the surface dipoles and in the bulk by neighboring dipoles. While the surface charge density formed through the dissociation of acidic and basic sites is decreased by the adsorption of counterions, the charges are replaced by ion pairs (dipoles) which polarize the water molecules nearby. This polar-... 

Substituting Eq. (23) into Eq. (22), a boundary condition for the surface charge density generated through the dissociation equilibrium is obtained. Equations (8) and (9) can be solved numerically for the boundary conditions (11)—(14), (23), to calculate the force between plates. 

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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