| Ions in mixed dielectric solvents: density profiles and osmotic pressure between charged interfaces. | |
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MedLine Citation:
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PMID: 19338312 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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The forces between charged macromolecules, usually given in terms of osmotic pressure, are highly affected by the intervening ionic solution. While in most theoretical studies the solution is treated as a homogeneous structureless dielectric medium, recent experimental studies concluded that, for a bathing solution composed of two solvents (binary mixture), the osmotic pressure between charged macromolecules is affected by the binary solvent composition. By adding local solvent composition terms to the free energy, we obtain a general expression for the osmotic pressure, in planar geometry and within the mean-field framework. The added effect is due to the permeability inhomogeneity and nonelectrostatic short-range interactions between the ions and solvents (preferential solvation). This effect is mostly pronounced at small distances and leads to a reduction in the osmotic pressure for macromolecular separations of the order 1-2 nm. Furthermore, it leads to a depletion of one of the two solvents from the charged macromolecules (modeled as planar interfaces). Lastly, by comparing the theoretical results with experimental ones, an explanation based on preferential solvation is offered for recent experiments on the osmotic pressure of DNA solutions. |
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Authors:
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Dan Ben-Yaakov; David Andelman; Daniel Harries; Rudi Podgornik |
Publication Detail:
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Type: Journal Article; Research Support, N.I.H., Intramural; Research Support, Non-U.S. Gov't |
Journal Detail:
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Title: The journal of physical chemistry. B Volume: 113 ISSN: 1520-6106 ISO Abbreviation: J Phys Chem B Publication Date: 2009 Apr |
Date Detail:
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Created Date: 2009-04-23 Completed Date: 2009-06-19 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 101157530 Medline TA: J Phys Chem B Country: United States |
Other Details:
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Languages: eng Pagination: 6001-11 Citation Subset: IM |
Affiliation:
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Raymond and Beverly Sackler School of Physics and Astronomy, Tel Aviv University, Ramat Aviv, Tel Aviv 69978, Israel. |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Alcohols
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chemistry* DNA / chemistry Ions / chemistry Macromolecular Substances / chemistry Osmotic Pressure Solvents / chemistry Surface Properties Thermodynamics Water / chemistry* |
| Chemical | |
Reg. No./Substance:
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0/Alcohols; 0/Ions; 0/Macromolecular Substances; 0/Solvents; 7732-18-5/Water; 9007-49-2/DNA |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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