DIFFUSE-DOUBLE LAYER AT A MEMBRANE-AQUEOUS INTERFACE MEASURED WITH X-RAY STANDING WAVES
DIFFUSE-DOUBLE LAYER AT A MEMBRANE-AQUEOUS INTERFACE MEASURED WITH X-RAY STANDING WAVES
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DOI：
10.1126/science.2321026
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发表时间：
1990-04-06
期刊：
影响因子：
56.9
通讯作者：
PENNER, TL
中科院分区：
文献类型：
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作者：
BEDZYK, MJ;BOMMARITO, GM;PENNER, TL
用长周期X射线驻波直接测量了带电聚合磷脂膜接触的电解质溶液中的离子分布。27埃厚的脂单分子膜被支撑在钨/硅反射镜上。在镜面上方产生的X射线驻波是由来自同步加速器的9.8千电子伏特X射线束的全外反射产生的。含有带负电荷的磷酸基团的膜表面被浸泡在稀氯化锌溶液中。测量了膜表面凝聚层中的锌离子浓度和扩散层中锌离子的分布随头基电荷的变化。弥漫层的德拜长度在3到58埃之间变化。计算结果与古伊-查普曼-斯特恩模型定性吻合。
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.