Analytical Methods for Photoinitiated Chemistry in Microscale Structures

该项目由光学科学与工程项目的分析与表面化学项目支持，涉及持续发展和应用时间分辨光量热法和拉曼光谱方法，用于表征微尺度域内短寿命光化学物质的动力学、能量学和分子结构。各种新方法将被用于检测在微米到纳米尺度内发生的非常快速的反应，例如在单层，薄膜和胶体系统中可能很明显。脉冲激光拉曼光谱将用于探测自由基链引发反应；光学发射的表面声波（SAW）将允许在薄膜的单层区域内检测聚合反应动力学；一种新的“光子爆发”光谱方法，包括激光激发荧光标记的颗粒和激光诱导的分析物包封脂质体破裂，将允许确定胶体介质内的颗粒大小分布和反应化学。这些技术是“尖端的”，将提供目前无法用于探测这些环境的技术。下一代信息、制造和医疗技术的进步将需要在纳秒级时间尺度上设计和/或探测微观区域的能力。犹他大学的Harris教授和他的学生将研究几种尖端的激光光谱技术，这些技术将允许表征发生在单个细胞内、材料的“应力-断裂”界面和/或其他小型结构内部的过程。

This project, supported under the Optical Science and Engineering initiative in the Analytical and Surface Chemistry Program, involves the continued development and application of time resolved photocalorimetric and Raman spectroscopic methods for the characterization of the kinetics, energetics, and molecular structure of short-lived photochemical species within microscale domains. A variety of novel methods will be pursued which will detect very fast reactions occurring within micron to nanometer dimensions, such as may be evident in monolayer, thin film, and colloidal systems. Pulsed-laser Raman spectroscopy will be used to probe free-radical chain initiation reactions; optically launched surface acoustic waves (SAW) will allow the detection of polymerization reaction kinetics within the monolayer region of thin films; a new `photon burst` spectroscopic method which involves the laser excitation of fluorescent-labeled particles and the laser-induced rupture of analyte encapsulated liposomes will allow the determination of particle size distribution and reaction chemistry within colloidal media. These techniques are `cutting- edge` and will offer technology not currently available for probing these environments. Next generation advances in the information, manufacturing, and medical technologies will require the ability to engineer and/or probe microscopic areas at nanosecond timescales. Professor Harris and his students at the University of Utah will pursue several cutting-edge laser spectroscopic techniques that will allow the characterization of processes occurring within single cells, at `stress-fracture` interfaces in materials and/or inside other miniaturized structures.