CAREER: Fluid Dynamics of Colloidal Crystal Film Deposition

CBET-0747917正极胶体晶体薄膜(CCF)正被开发为用于集成电路的光子晶体、超疏水表面和用于生化分离的固态筛分基质。胶体晶体薄膜由20层或更多层面心立方填充的纳米球(20-500 nm)组成。这些薄膜通常是通过纳米球的非稀释胶体悬浮液的流体自组装过程来沉积的。目前的CCF存在20-1000个球径范围内的无用缺陷，限制了器件的应用。溶剂挥发和电泳法在很大程度上是通过反复试验开发出来的，缺乏对主导物理学的基本理解。控制胶体晶体薄膜结构和减少薄膜缺陷的能力受到沉积过程中流体传输的复杂作用的限制。这些流动包括具有高体积分数悬浮和局部变化的粘度、密度、表面张力、电导率和介电常数的自由表面和电场的耦合。它们是时间相关的、三维的，并表现出广泛的时间和长度尺度，这使得它们很难建模和观察。本文研究了高体积分数胶体悬浮液在自由表面和电场作用下沉积胶体晶体薄膜的输运物理。为了实时、实时地测量晶体的三个速度分量和晶体结构，将研制一台高速旋转圆盘共聚焦显微镜。这项研究将使沉积无缺陷的胶体晶体薄膜和结构成为一系列新兴技术的基础。高速共聚焦系统将影响范围广泛的学科，包括微流体学、流变学、胶体科学和实时细胞成像。胶体结晶的基础知识可以应用于分子结晶，如蛋白质结晶学。该计划将研究与指导、教育和外展相结合，影响着从中学到研究生院的学生。这项研究包括发展中学外展计划？有没有心流？？为凤凰城大都市区未被充分代表的中学生提供服务。？有流量？？该计划有三个阶段：直接激励1000名8年级学生学习数学、科学或工程的外展模块；为中学教师提供研究经验和国家规定的专业培训的RET；以及将这些模块传递给个别中学的教育转移模块(ETM)。PI将扩大西班牙裔和美洲原住民的本科生研究机会，这些人在亚利桑那州立大学的入学率相对较高，但在全国工程学领域的代表性较低。

CBET-0747917PosnerColloidal crystal films (CCF) are being developed as photonic crystals for integrated optical circuits, as super hydrophobic surfaces, and as solid-state sieving matrices for biochemical separations. Colloidal crystal films are comprised of 20 or more layers of face center cubic packed nanospheres (20-500 nm). These films are typically deposited by a fluid self-assembly process of a non-dilute colloidal suspension of nanoscale spheres. Current CCFs are plagued with unwanted defects in the range of 20-1000 sphere diameters that limit device applications. Solvent evaporation and electrophoretic deposition methods are largely developed by trial and error and suffer from a lack of fundamental understanding of the governing physics. The ability to control colloidal crystal film structure and reduce film defects is limited by the complex role of the fluid transport on the deposition process. These flows include the coupling of free surfaces and electric fields with high volume fraction suspensions and locally varying viscosity, density, surface tension, conductivity, and permittivity. They are time-dependent, three-dimensional and exhibit a wide range of time and length scales that make them difficult to model and observe. This research investigates the transport physics of colloidal crystal film deposition where high volume fraction colloidal suspensions flow with free surfaces and electric fields. A high-speed, spinning disk confocal microscope will be developed to measure the three velocity components and crystal structure in real-time and real-space. This research will enable depositions of defect-free colloidal crystal films and structures for a host of emerging technologies. The high speed confocal system will impact a wide range of disciplines including microfluidics, rheology, colloidal science, and real-time cellular imaging. Fundamental understanding of colloidal crystallization can be applied to molecular crystallization such as protein crystallography. This program integrates research with mentoring, education and outreach impacting students from middle school through graduate school. The study includes the development of a middle school outreach program ?got flow?? for underrepresented middle school students in the Phoenix metropolitan area. The ?got flow?? program has three phases: outreach modules directly inspiring 1000 8th graders to study math, science, or engineering; RET to provide research experience and state mandated professional training for middle school teachers; and educational transfer modules (ETM) that convey the modules to individual middle schools. The PI will expand undergraduate research opportunities for Hispanic and Native Americans who have relatively high enrollment at ASU, but low representation in engineering nationwide.