Size determination of shear-induced multilamellar vesicles by rheo-NMR spectroscopy.
Size determination of shear-induced multilamellar vesicles by rheo-NMR spectroscopy.
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DOI：
10.1021/la903682p
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发表时间：
2010-02
期刊：
影响因子：
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通讯作者：
B. Medronho;C. Schmidt;U. Olsson;M. Miguel
中科院分区：
文献类型：
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作者：
B. Medronho;C. Schmidt;U. Olsson;M. Miguel
提出了一种分析表面活性剂多层囊泡（MLV，“洋葱”）体系中D(2)O的氘(2)H) NMR谱线形状的模型。相邻层间水分子缓慢交换的假设意味着(2)H核磁共振谱线形状可以简单地由洛伦兹量和给出，如果也满足运动变窄的条件。利用结构化流体中核磁共振弛缓的经典两步模型，我们可以计算核磁共振线的形状如何取决于MLV的大小。该模型在两种不同的MLV系统上进行了测试，其中使用流变核磁共振测量了核磁共振线形作为应用剪切速率的函数。所得的MLV尺寸与前人的流变小角光散射数据吻合较好。
A model for analyzing the deuterium ((2)H) NMR line shapes of D(2)O in surfactant multilamellar vesicle (MLV, "onion") systems is proposed. The assumption of the slow exchange of water molecules between adjacent layers implies that the (2)H NMR line shape is simply given by a sum of Lorentzians if the condition of motional narrowing is also fulfilled. Using the classical two-step model for the NMR relaxation in structured fluids allows us to calculate how the NMR line shape depends on the MLV size. The model is tested on two different MLV systems for which the NMR line shapes are measured as a function of the applied shear rate using rheo-NMR. The MLV sizes obtained are in good agreement with previous data from rheo-small-angle light scattering.