Investigation of Microsphere Convective Deposition for Photonic and Biological Applications

CBET-0828426 Gillian拟议的研究将产生一个基本的描述，涉及使用对流自组装的粒子单层沉积的物理。将蒸发弯月面拉过衬底，这是一种与“咖啡环效应”和Langmuir-Blodgett技术相关的工艺，形成了从随机和有序的亚单层到有序多层的颗粒结构。虽然许多最近开发的过程利用这种技术，主要问题仍然涉及粒子对流和自组装的基本物理。单层沉积的原位研究将使用高速共聚焦激光扫描显微镜进行。初步结果表明，许多参数没有以前考虑影响沉积和各种机制产生微球预对准薄膜沉积前。将先前未探索的加工、悬浮和衬底条件结合起来的实验将用于开发模型，以揭示将可控宏观特性与微观结构联系起来的机制。胶体单层的制造将直接用于两个具体的应用。InGaN发光二极管（LED）的性能受到GaN/空气界面的折射率失配的抑制。所提出的工艺将用于制造微透镜阵列，其中微结构决定光提取效率。初步结果表明，光输出功率增加了219%。在一个平行的努力，单层阵列的设计与抗体标记的全血检测的CD 4+淋巴细胞将能够增强筛选艾滋病毒/艾滋病。这些沉积的单层的微结构将决定靶细胞的捕获效率和增殖，并使这些细胞能够释放用于分析。更广泛的影响：虽然胶体对流沉积被用于许多技术，但基本物理学知之甚少。这项研究将开发一个预测模型的基础上获得的观察直接三维粒子跟踪沉积过程中的各种表面和悬浮液的属性。通过这项研究，控制这种微观结构的重要性将在两个对各自行业具有重大潜在影响的应用中得到证明。首先，使用该技术制造的微透镜阵列具有超越当前最先进的LED光子提取的潜力，允许工业应用的规模扩大，并且与通过电子束光刻的表面图案化的当前技术相比是低成本的。在全血分析中，这种技术可以推广到各种检测方案，并将有助于开发一种旨在为缺乏适当医疗资源的地区带来低成本检测的方法。这项工作将直接提供研究生和本科生的教育机会，在几个技术关键的研究领域，包括微流体，悬浮运输，光子学和生物工程的融合领域。

CBET-0828426GilchristThe proposed research will generate a fundamental description of the physics involved in the deposition of a monolayer of particles using convective self-assembly. Drawing an evaporating meniscus across a substrate, a process related to the "coffee ring effect" and the Langmuir-Blodgett technique, forms a structure of particles ranging from random and ordered sub-monolayer to well-ordered multilayers. Although many recently developed processes take advantage of this technique, primary questions remain regarding the fundamental physics involved with particle convection and self-assembly. In situ investigation of monolayer deposition will be performed using high speed confocal laser scanning microscopy. Preliminary results suggest many parameters not previously considered affect deposition and various mechanisms generate microsphere pre-alignment in the thin film prior to deposition. Experiments that incorporate processing, suspension, and substrate conditions not previously explored will be used to develop a model to shed light onto the mechanisms that link the controllable macroscopic properties to the microstructure. Fabrication of colloidal monolayers will be used directly in two specific applications. Performance of InGaN light emitting diodes (LEDs) is inhibited by the index mismatch of the GaN/air interface. The proposed process will be used to fabricate microlens arrays where the microstructure determines the light extraction efficiency. Preliminary results demonstrate increased light output power by 219%. In a parallel effort, design of monolayer arrays labeled with antibodies for whole blood detection of CD4+ lymphocytes will enable enhanced screening for HIV/AIDS. The microstructure of these deposited monolayers will dictate the capture efficiency and proliferation of target cells and enable release of these cells for analysis. Broader Impacts: Although colloidal convective deposition is used in many technologies, the fundamental physics is poorly understood. This research will develop a predictive model based on observations obtained from direct 3D particle tracking during deposition for various surface and suspension properties. Through this research, the importance of controlling this microstructure will be demonstrated in two applications that have significant potential impact on their respective industries. First, the microlens arrays fabricated using this technique have the potential to surmount the current state-of-the-art LED photon extraction, allows scale-up for industrial applications, and is low-cost as compared to current techniques of surface patterning via electron beam lithography. In whole blood analysis, this technique can be generalized for a variety detection schemes and will aid development of a process that aims to bring low cost detection to regions lacking proper medical resources. This work will directly provide both graduate and undergraduate educational opportunities in an area at the convergence of several technologically-critical research areas including microfluidics, suspension transport, photonics, and bioengineering.