Phase Transitions in Colloidal Suspensions of Disks

圆盘胶体悬浮液中的相变

• 批准号: 1006870
• 负责人: Zhengdong Cheng
• 金额: $ 29.4万
• 依托单位: Texas A&M Engineering Experiment Station
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-07-15 至 2014-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1006870&HistoricalAwards=false
• 关键词: Phase; Transitions; Colloidal; Suspensions; Disks

Non-Technical Abstract: Despite their natural abundance and wide industrial applications, such as red blood cells and clay, disks are least studied compared to spheres and rods. This condensed matter physics project will establish the long waited model micro-disks using unique methodology, shape transformation of liquid crystal emulsions and exfoliation of layered inorganic crystals. Micro-disks will be mass-produced with unprecedented uniformity in size and shape, and unprecedented flexibility in the control of size, shape, size-polydispersity and aspect ratio. Underlining the unique flow characteristics and applications of disk materials, the discotic liquid crystal phase transitions will be investigated experimentally and theoretically regarding their dependence on inter-disk interactions, disk aspect ratio and polydispersity. The achievement of controlled organization of discotic molecules and colloids will impact industries such as pharmaceuticals, medicine, oil refining, chemical process, solar energy, nano-composite engineering and photonics. Colloidal discotics will help to unleash the educational power of complex fluids as models of atomic discotic liquid crystals and tangible elements of the macroscopic world. This project will use visualization and multimedia tools to train graduates, to build educational modules for undergraduates, and to attract k-12 students into scientific research. It will also establish collaborations around the world to enhance the global impact of its research and education program. Technical Abstract: This condensed matter physics project will use unique methodology (shape transformation of liquid crystal emulsions and exfoliation of layered inorganic crystals) to mass-produce micro-disks with unprecedented uniformity in size and shape, and unprecedented flexibility in the control of size, shape, size-polydispersity and aspect ratio. The discotic liquid crystal phase transitions isotropic or liquid-like to orientationally order or nematic (I-N), nematic to crystal (N-C), and nematic to ordered layer-like or smectic (N-S) will be investigated experimentally. The nematic-to-smectic (N-S) transition is one of the main unsolved problems in statistical physics. Theory will be constructed and experimentally tested regarding the dependence of phase transitions on inter-disk interactions (screened electrostatic repulsion, depletion attraction), aspect ratio and polydispersity. The achievement of controlled organization of discotic molecules and colloids will impact industries such as pharmaceuticals, medicine, oil refining, chemical process, solar energy, nano-composite engineering and photonics. Colloidal discotics will help to unleash the educational power of complex fluids as models of atomic discotic liquid crystals and tangible elements of the macroscopic world. This project will use visualization and multimedia tools to train graduates, to build educational modules for undergraduates, and to attract K-12 students into scientific research. It will also establish collaborations around the world to enhance the global impact of its research and education program.

非技术摘要：尽管圆盘具有天然的丰度和广泛的工业应用，如红细胞和粘土，但与球体和棒材相比，对圆盘的研究最少。这项凝聚态物理计划将利用独特的方法学、液晶乳剂的形状变换和层状无机晶体的剥离来建立期待已久的模型微盘。微盘将以前所未有的大小和形状的一致性以及在大小、形状、大小多分散性和纵横比的控制方面的前所未有的灵活性进行大规模生产。为了强调盘状材料独特的流动特性和应用，将从实验和理论上研究盘状液晶相变对盘间相互作用、盘状纵横比和多分散性的依赖关系。盘状分子和胶体可控组织的实现将对制药、医药、炼油、化工、太阳能、纳米复合材料工程和光子学等行业产生影响。胶体毒品将有助于释放复杂流体作为原子盘状液晶和宏观世界有形元素的模型的教育力量。该项目将使用可视化和多媒体工具来培训毕业生，为本科生建立教育模块，并吸引K-12学生进入科学研究。它还将在世界各地建立合作，以增强其研究和教育计划的全球影响力。技术摘要：这个凝聚态物理项目将使用独特的方法(液晶乳剂的形状变化和层状无机晶体的剥离)来批量生产尺寸和形状前所未有的均匀微盘，以及在尺寸、形状、尺寸多分散性和纵横比控制方面前所未有的灵活性。实验研究了盘状液晶从各向同性或类液体到定向有序或向列相(I-N)，向列相到晶体(N-C)，向列相到有序层状或近晶相(N-S)的相变。向列相到近晶相(N-S)的相变是统计物理中尚未解决的主要问题之一。关于相变对盘间相互作用(屏蔽静电斥力、耗尽吸引)、长宽比和多分散性的依赖关系，将建立理论并进行实验测试。盘状分子和胶体可控组织的实现将对制药、医药、炼油、化工、太阳能、纳米复合材料工程和光子学等行业产生影响。胶体毒品将有助于释放复杂流体作为原子盘状液晶和宏观世界有形元素的模型的教育力量。该项目将使用可视化和多媒体工具来培训毕业生，为本科生建立教育模块，并吸引K-12学生进入科学研究。它还将在世界各地建立合作，以增强其研究和教育计划的全球影响力。