Polarized Raman scattering and SEM combined full characterization of self-assembled nematic thin films.
Polarized Raman scattering and SEM combined full characterization of self-assembled nematic thin films.
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DOI：
10.1039/c6nr01440b
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发表时间：
2016-03
期刊：
影响因子：
6.7
通讯作者：
R. Srikantharajah;K. Gerstner;Stefan Romeis;Wolfgang Peukert
中科院分区：
文献类型：
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作者：
R. Srikantharajah;K. Gerstner;Stefan Romeis;Wolfgang Peukert
细长颗粒注定能够沿优选方向快速传输光信号和电信号，这对于光电器件的快速响应是必需的。该材料的性能基于颗粒的无缺陷排列的质量。在这个帐户上，我们提出了一个简单的非侵入性的方法来表征表面和批量订单。通过映射在大面积上偏振拉曼散射信号的取向相关变化来进行体序的表征。表面的扫描电子显微镜和图像分析完成表征。在浸涂纳米棒结构中的新见解清楚地显示了蒸发诱导和剪切诱导的自组装的相互作用，并揭示了纳米棒组装的全面机械图：剪切力主导的制度使颗粒沿撤回方向取向。然而，在低抽出速度下，剪切力和蒸发抵消以产生三层膜，其中顶层和底层彼此垂直取向。中间层给出了一个明确的证据，对流重定向。
Elongated particles are predestined for a fast transfer of optical and electronical signals in a preferred direction, which is mandatory for a quick response in optoelectronic devices. The performance of the material is based on the quality of defect less alignment of the particles. On this account we present an easy non-invasive methodology for characterization of both surface and bulk order. The characterization of bulk order is performed by orientation dependent variation of the polarized Raman scattering signal on large areas by mapping. Scanning electron microscopy and image analysis on the surface complete the characterization. New insights in dip coated nematic structures clearly show the interplay of evaporation induced and shear-induced self-assembly and reveal a comprehensive mechanistic picture for nanorod assembly: the shear force dominated regime orients the particle in direction of withdrawal. At low withdrawal velocity, however, shear forces and evaporation counteract to produce a three-layered film where the top and bottom layers are oriented perpendicular to each other. The middle layer gives a clear evidence for a reorientation by convective flow.