Electrostatic interaction nonuniformly charged

Electrostatic Interaction Between Nonuniformly Charged Membranes... 

The distinguishing feature of dehydrated zeolites as microporous aluminosilicate adsorbents lies in the presence in their voids—i.e., micropores—of cations. These cations compensate excess negative charges of their aluminosilicate skeletons. The cations form, in the zeolite micropores, centers for the adsorption of molecules with a nonuniform distribution of the electron density (dipole, quadrupole, or multiple-bond molecules) or of polarizable molecules. These interactions, which will be called, somewhat conventionally, electrostatic interactions, combine with dispersion interactions and cause a considerable increase in the adsorption energy. As a result, the adsorption isotherms of vapors on zeolites, as a rule, become much steeper in the initial regions of equilibrium pressures as compared with isotherms for active carbons. 

The joint effect of EOF nonuniformity and particle-wall electrostatic interactions was studied in Ref. 4. Two types of solute particles were examined one with the charge of the same sign as the zeta potential of the wall, and the other of the opposite sign. The particles of the first type are moving electrophoretically in the direction opposite to the direction of EOF and are elec-... 

This behavior should be especially apparent in the case of an uncharged surface. For adsorption at ionic surfaces the main factor is, probably, the net opposite charge of the protein molecule, which may contribute to the enthalpic part of the adsorption free energy. At the same time, a nonuniform distribution of ionic patches on the surface of a protein can lead to attractive electrostatic interactions between the patches and the surface even when the net charge of the protein is of the same type as that of the surface [18]. 

Around these charges, a well-defined layer (the Stem layer) of ions of opposite sign (counterions) to that of the surface ions is formed. In addition, as a result of electrostatic interactions and thermal motion of the molecules, a nonuniform diffuse second layer develops around the particles which is composed mainly of... 

The charge nonuniformity on the surface of colloidal particles may also significantly contribute to the electrostatic interactions. It can arise from selective ion adsorption on the surface of colloidal particles and distribution of C potential [45, 46]. The surface charge nonuniformity can lead to attractive electrostatic and hydrophobic interactions between particles and cause suspension instability [47-49]. An extension of the HHF model for the randomly charged surfaces gives the following Velegol-Thwar potential [46] ... 

M. L. Grant and D. A. Saville, J. Colloid Interface Sci., 171, 35 (1995). Electrostatic Interactions between a Nonuniformly Charged Sphere and a Charged Surface. 

Across real surfaces and interfaces, the dielectric response varies smoothly with location. For a planar interface normal to a direction z, we can speak of a continuously changing s(z). More pertinent to the interaction of bodies in solutions, solutes will distribute nonuniformly in the vicinity of a material interface. If that interface is charged and the medium is a salt solution, then positive and negative ions will be pushed and pulled into the different distributions of an electrostatic double layer. We know that solutes visibly change the index of refraction that determines the optical-frequency contribution to the charge-fluctuation force. The nonuniform distribution of solutes thereby creates a non-uniform e(z) near the interfaces of a solution with suspended colloids or macromolecules. Conversely, the distribution of solutes can be expected to be perturbed by the very charge-fluctuation forces that they perturb through an e(z).5... 

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