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PubMed · 2321026

Diffuse-double layer at a membrane-aqueous interface measured with x-ray standing waves.

M J Bedzyk·G M Bommarito·M Caffrey·T L Penner
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Abstract

The ion distribution in an electrolyte solution in contact with a charged polymerized phospholipid membrane was directly measured with long-period x-ray standing waves. The 27-angstrom-thick lipid monolayer was supported on a tungsten/silicon mirror. X-ray standing waves were generated above the mirror surface by total external reflection of a 9.8-kiloelectron volt x-ray beam from a synchrotron undulator. The membrane surface, which contained negatively charged phosphate headgroups, was bathed in a dilute ZnCl2 solution. The concentration of Zn2+ in the condensed layer at the membrane surface and the Zn2+ distribution in the diffuse layer were measured as a function of headgroup charge. The Debye length of the diffuse layer varied between 3 and 58 angstroms. The results qualitatively agree with the Gouy-Chapman-Stern model.

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Chemical PhenomenaChemistry, PhysicalElectrochemistryElectrolytesHydrogen-Ion ConcentrationMembranes, ArtificialParticle AcceleratorsPhospholipidsPolymersSolutionsWaterX-RaysZincJournal ArticleResearch Support, Non-U.S. Gov'tResearch Support, U.S. Gov't, Non-P.H.S.Research Support, U.S. Gov't, P.H.S.

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M J Bedzyk, G M Bommarito, M Caffrey, T L Penner. 1990-04-06. Diffuse-double layer at a membrane-aqueous interface measured with x-ray standing waves.. https://doi.org/10.1126/science.2321026

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