Complex Fluids With Extended, Rigid Components

该项目将提高对包含刚性成分的复杂流体中的缠结和纤细结构的理解。它将包括在纠缠和非纠缠聚合物溶液中刚性棒的旋转和平移的研究。模型系统由烟草花叶病毒和线性或球状葡聚糖组成。相关实验关注液晶中的扩散输运，强调合成可变长度多肽以确定柔性的影响。十二烷中聚硬脂酰谷氨酸的表征将阐明这种可能是所有可逆凝胶中最简单的独特性质。自组装的研究，双向树将强调基本性质，如稳定性。同样重要的是控制自组装的机制。技术包括静态和动态光散射、荧光光漂白回收、脉冲场梯度核磁共振波谱和待开发的双折射方法。具有刚性、扩展组分的复杂流体是高强度纤维和薄膜的重要前体。它们也提出了非常具有挑战性的基本问题，比如纠缠的性质。这些实验将为其他地方的理论发展提供观察结果，共同为合理设计和加工更好的材料奠定基础。偶然发现的机会是存在的，特别是在自组装的树状体中，它显示出不寻常的长程结构的初步迹象。潜在的应用包括衍射光栅和其他光学器件，用于提高分析分离通量的优越固定相，以及用于控制聚合物/胶体稳定性的更有效系统，这在环境修复和纳米制造中很重要。学生和其他人将在一个将课堂和实践实验室教育与基础研究以及与工业和其他校外科学家合作的氛围中工作。

The project will lead to improved understanding of entanglements and tenuous structures in complex fluids containing rigid components. It will include a study of the rotation and translation of rigid rods in entangling and non-entangling polymer solutions. The model system here is composed of tobacco mosaic virus and linear or globular dextran. Related experiments concern diffusive transport in liquid crystals, emphasizing synthetic polypeptides of variable length to determine the effects of flexibility. Characterization of poly(stearylglutamate in dodecane will illuminate the unique properties of this, perhaps the simplest of all reversible gels. Studies of self-assembling, two-directional arborols will emphasize basic properties such as stability. Equally important are the mechanisms by which the self-assembly can be controlled. Techniques include static and dynamic light scattering, fluorescence photobleaching recovery, pulsed field gradient NMR spectroscopy, and to-be-developed birefringence methods.Complex fluids with rigid, extended components are important precursors to high-strength fibers and films. They also pose very challenging fundamental questions, such as the nature of entanglements. The experiments will provide the observations to support theoretical developments elsewhere, creating together the underpinnings for rational design and processing of better materials. Good chances for serendipitous discovery exist, particularly in the self-assembling arborols, which show preliminary signs of unusual long-range structures. Potential applications include diffraction gratings and other optical devices, superior stationary phases for enhanced throughput in analytical separations, and more efficient systems for control of polymer/colloid stability, which is important in environmental remediation and nanofabrication. Students and others will work in an atmosphere that blends classroom and practical laboratory education with fundamental research and partnership with industrial and other off-campus scientists.