Low dielectric interface

Comparing the results obtained by the WKB method with the exact solutions for the planar and spherical surface, we find, within 2% error, quantitative agreement in the planar case. For a sphere, we find the same asymptotic dependence of critical adsorption behavior for a wide range of geometries. The main advantage of the WKB method is a unified approach for the various geometries based on the same level of approximations. It can be applied at the same level of complexity to virtually any shape of the polylectrolyte-surface adsorption potential. Recent advances in polyelectrolyte adsorption under confinement [49,167] and adsorption onto low-dielectric interfaces [50] have been presented. 

Low-Dielectric Interfaces— The presence of a low-dielectric material beneath the adsorbing boundary has considerable implications for adsorption. In particular, in the proximity of such an interface the polyelectrolyte experiences a repulsive force from the image charges that effectively displace the polymer from the interfacial region of a high attractive potential. This image repulsion grows... 

The issue of critical polyelectrolyte adsorption is intimately coupled to the polymer-mediated bridging attraction between oppositely charged macro-ions immersed in a polymer solution. Moreover, electrostatically driven self-assembly of single-stranded RNA molecules on the interior of positively charged capsids, as it occurs in many spherical and rod-Uke single-stranded viruses, offers another field for potential applications of our theoretical results. The WKB method developed above has recently been implemented to weak polyelectrolyte adsorption under confined conditions [49] and to adsorption onto low-dielectric interfaces [50]. The power of the WKB approach can even be extended to more complicated adsorption situations, such as patchy surfaces, specific charged patterns on concave and convex interfaces, Janus particles, etc., and other (nearly arbitrary) potentials of polyelectrolyte-surface interactions. This might open an avenue to approach more realistic situations of polyelectrolyte adsorption and to quantitatively reproduce experimental results in the future. 

Experimental as well as theoretical studies of anions close to the vapour-water and molecular interfaces reveal an appreciable ion specific segregation. In particular large, soft and poorly hydrated ions such as iodide and thiocyanate are attracted to the interface while small, hard and well-solvated species are repelled from it. The former observation contradicts the traditional dielectric continuum picmre within which a generic, solvated ion close to a low dielectric interface will experience a repulsive force due to partial dehydration. Let us revise the mechanisms with which an ion may interact with a nonpolar interface ... 

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See also in sourсe #XX -- [ , ]

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