Investigation of Microsphere Convective Deposition for Photonic and Biological Applications

用于光子和生物应用的微球对流沉积研究

• 批准号: 0828426
• 负责人: James Gilchrist
• 金额: $ 30万
• 依托单位: Lehigh University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-08-15 至 2012-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0828426&HistoricalAwards=false
• 关键词: Investigation; Microsphere; Convective; Deposition; Photonic

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.

拟议的研究将产生一个基本的物理描述，涉及到利用对流自组装沉积单层粒子。在衬底上画一个蒸发的半月板，这是一个与“咖啡环效应”和Langmuir-Blodgett技术相关的过程，形成了从随机有序的亚单层到有序的多层的粒子结构。尽管最近开发的许多工艺都利用了这种技术，但有关粒子对流和自组装的基本物理问题仍然存在。在原位调查单层沉积将进行高速共聚焦激光扫描显微镜。初步结果表明，许多先前未考虑的参数会影响沉积，并且各种机制会在沉积前在薄膜中产生微球预对准。将先前未探索的加工、悬浮和衬底条件结合在一起的实验将用于开发一个模型，以阐明将可控宏观特性与微观结构联系起来的机制。胶体单分子层的制造将直接用于两个特定的应用。氮化镓（InGaN）发光二极管（led）的性能受到氮化镓/空气界面指数失配的抑制。所提出的工艺将用于制造微透镜阵列，其中微观结构决定了光提取效率。初步结果表明，光输出功率提高了219%。与此同时，设计带有抗体的单层阵列，用于全血检测CD4+淋巴细胞，将增强对艾滋病毒/艾滋病的筛查。这些沉积单层的微观结构将决定靶细胞的捕获效率和增殖，并使这些细胞释放用于分析。更广泛的影响：尽管胶体对流沉积在许多技术中都有应用，但对其基本物理原理了解甚少。本研究将基于沉积过程中直接3D粒子跟踪所获得的各种表面和悬浮特性的观察结果，开发一个预测模型。通过这项研究，控制这种微观结构的重要性将在两种对各自行业具有重大潜在影响的应用中得到证明。首先，使用这种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，可以扩大工业应用的规模，并且与目前通过电子束光刻的表面图案化技术相比成本低。在全血分析中，该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过程。这项工作将直接提供研究生和本科生的教育机会，在几个技术关键研究领域的融合，包括微流体，悬浮运输，光子学和生物工程。