Analytical Methods for Photoinitiated Chemistry in Microscale Structures

该项目由分析和表面化学计划中的光学科学和工程倡议支持，涉及继续开发和应用时间分辨光量热和拉曼光谱方法，以表征微尺度范围内短寿命光化学物种的动力学、能量和分子结构。将寻求各种新的方法来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。将使用脉冲激光拉曼光谱探测自由基链引发反应；光学发射表面声波(SAW)将能够检测薄膜单层区域内的聚合反应动力学；涉及荧光标记颗粒的激光激发和分析物包裹的脂质体的激光诱导破裂的新的“光子爆发”光谱方法将能够确定胶体介质中的颗粒尺寸分布和反应化学。这些技术是尖端技术，将提供目前无法探测这些环境的技术。信息、制造和医疗技术的下一代进步将需要在纳秒时间尺度上设计和/或探测微观区域的能力。哈里斯教授和他在犹他大学的学生将学习几种尖端的激光光谱技术，这些技术将能够描述发生在单个细胞内、材料中的应力-断裂界面和/或其他微型化结构中的过程。

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.