Microscopy, diffraction and spectroscopy of surfactant monolayer films

本课题在表面活性剂薄膜方面的研究目标是：(1)研究一种新型阴离子双子星表面活性剂组成的单层膜的分子水平结构-功能关系；(2)利用单分子荧光光谱研究多荧光*光聚合物薄膜中的电子能量传递动力学；*(3)开发先进的光谱工具，用于表征空气-水界面的单层。该计划将产生基础知识，为我们小组的研究提供应用方面的信息，包括作物保护和食用油封装工作，并在对加拿大经济重要的领域提供高水平的HQP培训。***在课程期间，*我们将研究：(1)由一类新发现的阴离子双子星表面活性剂组成的单层膜的基本结构-功能关系。感兴趣的关键问题是表面活性剂的分子结构如何影响基本的单层性质，包括横向堆积密度、离子结合能力、机械稳定性和剪切流变性。研究将涉及化学合成支持的单层的热力学、微观和基于衍射的结构表征，以根据需要制备定制表面活性剂。(2)薄膜中耦合发光分子中调节电子能量传递效率的分子水平因素。感兴趣的系统是由可聚合表面活性剂制备的荧光聚二乙炔薄膜。我们将测量这些薄膜中的能量转移效率，并将光聚合物中单个荧光团的排列与能量转移动力学联系起来。测量*将使用单分子荧光各向异性成像结合传统荧光*测量支持量子化学计算。(3)用于测量气-水界面膜分子级结构的新光谱工具，包括偏振调制红外反射吸收光谱和和频产生振动光谱。前者将利用独特的高强度同步辐射来实现前所未有的时间分辨率，而后者将建立在我们在皮秒和飞秒激光仪器方面的专业知识。该计划将推进材料科学的基础研究，为应用表面活性剂的研究提供信息，并在国家重要领域提供世界级的HQP培训。

The goals of this*research program in surfactant films are: (1) to investigate molecular-level structure-function*relationships in monolayer films comprised of a new type of anionic gemini*surfactant; (2) to investigate electronic energy transfer dynamics in multifluorophoric*photopolymer films using single-molecule fluorescence spectroscopy; and*(3) to develop cutting-edge spectroscopy tools for molecular-level characterization*of monolayers at the air-water interface. The program will generate fundamental*knowledge that will inform applied aspects of our group's research, including work*on crop protection and edible oil encapsulation, as well as provide high-caliber*training of HQP in areas of economic importance to Canada.*** Over the program's duration,*we will investigate: (1) Fundamental structure-function relationships in monolayer*films comprised of a newly-discovered class of anionic gemini surfactants. The key issue of interest is how the molecular structure of surfactants affects fundamental monolayer properties including lateral packing*density, ion-binding capacity, mechanical stability and shear rheology. Studies will involve thermodynamic,*microscopic and diffraction-based structural characterization of monolayers supported*by chemical synthesis to prepare custom surfactants as required. (2) Molecular-level*factors that regulate electronic energy transfer efficiency in coupled, luminescent*molecules in thin films. The systems of*interest are fluorescent polydiacetylene films prepared from polymerizable*surfactants. We will measure energy*transfer efficiency in these films and correlate alignment of individual*fluorophores in the photopolymers with energy transfer dynamics. Measurements*will use single-molecule fluorescence anisotropy imaging in combination with traditional fluorescence*measurements supported by quantum chemical calculations. (3) New*spectroscopic tools for measuring molecular-level structure of films at the*air-water interface, including polarization modulated infrared reflection absorption*spectroscopy and sum frequency generation vibrational spectroscopy. The former will make use of unique,*high-intensity synchrotron radiation to enable unprecedented temporal resolution,*and the latter will build on our expertise with pico- and femtosecond laser instrumentation. This program will advance fundamental research*in materials science, inform applied surfactant research and provide*world-class training of HQP in areas of national importance.