Liquid Crystals in Complex Fluid Systems

[9974388] meyer本项目研究的主题是液晶凝胶系统，以及近晶液晶薄膜的对称性和纹理。在液晶凝胶领域，我们将进行实验来探索凝胶网络与向列液晶的耦合，这赋予了该体系独特的性能。将进行电光显微镜实验，包括研究样品响应的对称性，以及作为施加电压和样品厚度的函数的畴壁的形成。宏观和微观力学实验将直接观察凝胶-向列耦合，并将探索凝胶微球作为有用的实验几何。将研究微晶薄膜，比较液体表面的独立薄膜和极性薄膜，特别注意由于薄膜对称性的变化而导致的纹理变化。根据这些系统的自由能模型，将进行计算以试图解释观察到的纹理。实验方法包括偏振光视频显微镜，以及用电场和光镊（高度聚焦的激光束）操纵样品纹理。对向列凝胶中电光效应的结构和分子性质以及近晶薄膜中的对称性和织构的基础研究，对于理解和优化平板显示器件中液晶的静态和动态行为具有重要意义。这种涉及物理、化学和生物的研究的更广泛的教育影响为高中学生通过博士后培训提供了一个很好的培训场所。

9974388MeyerThis project addresses the topics of liquid crystal gel systems, and symmetry and textures in thin films of smectic liquid crystals. In the area of liquid crystal gels, experiments will be carried out to explore the coupling of the gel network to the nematic liquid crystal, which imparts unique properties to this system. Electro-optical microscopy experiments will be performed, including studies of the symmetry of the sample response, and the formation of domain walls, as a function of applied voltage and sample thickness. Macroscopic and microscopic mechanical experiments will be performed to observe directly the gel-nematic coupling, and gel microspheres will be explored as a useful experimental geometry. Thin smectic films will be studied, comparing free standing films with polar films on the surface of a liquid, with special attention to the changes in texture resulting from the change in symmetry of the film. Computations will be carried out to try to account for the observed textures, in terms of models for the free energy of these systems. Experimental methods include polarized light video microscopy, and manipulation of the sample texture with electric fields and optical tweezers, which are highly focused laser beams.Fundamental studies of the structural and molecular properties of electro-optic effects in nematic gels and the symmetry and textures in thin smectic films is relevant to understanding and optimizing the static and dynamic behavior of liquid crystals in flat panel display devices. The broader educational impact of this kind of research involving physics, chemistry and biology provides an excellent training ground for students from high school through post-doctoral training.