Determination of the thickness and optical properties of a Langmuir film from the domain morphology by Brewster angle microscopy
Determination of the thickness and optical properties of a Langmuir film from the domain morphology by Brewster angle microscopy
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DOI：
10.1021/la9713154
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发表时间：
1998-04-28
期刊：
影响因子：
3.9
通讯作者：
Mann, JA
中科院分区：
文献类型：
--
作者：
de Mul, MNG;Mann, JA
发展了一种利用布鲁斯特角显微镜测量空气-水界面单分子膜和多层膜相对厚度的方法。结果表明，8 CB（4 '-n-alkyl[1，1'-biphenyl]-4-carbonitrile; nCB，n = 8）在空气-水界面上的多层膜是由一个或两个双层叠置在单层膜上形成的。此外，风扇纹理的混合展曲弯曲向错缺陷，这是形成在10 CB单层上的连续三层的反向崩溃，被用来获得估计的各向异性介电常数的单分子膜的组件。通过比较实验图像与基于缺陷周围的假定指向矢分布的计算生成的模型图像来进行该估计。研究结果支持了相对于凝聚机制的多层生成和反向坍塌的折叠机制的有效性。最后，多层膜厚度和单层膜厚度之比的实验值和理论值的比较表明，在这一水平的水膜界面不能被假定为尖锐的或明确的。
A method employing Brewster angle microscopy was developed to measure the relative thickness of monolayers and multilayers at the air-water interface. Results proved that multilayers in ultrathin films of 8CB (4'-n-alkyl[1,1'-biphenyl]-4-carbonitrile; nCB, n = 8) are built up from one or two stacked bilayers on top of a monolayer at the air-water interface covered by a continuous bilayer. In addition, the fan texture of the mixed splay-bend disclination defects, which are formed in 10CB monolayers on reverse collapse of a continuous trilayer, was used to obtain estimates for the components of the anisotropic dielectric constant of the monomolecular film. This estimate was made by comparing experimental images with computationally generated model images based on an assumed director distribution around the defect. The results support the validity of the folding mechanism of multilayer generation and reverse collapse as opposed to the condensation mechanism. Finally, comparison of the experimental and theoretical values of the ratio of the multilayer thickness and the monolayer thickness indicates that at this level the water-film interface cannot be assumed to be sharp or well defined.