In-Situ Transmission Electron Microscopy of the Electrochemical Deposition of Functionalized Poly(thiophenes)

第1部分：非技术概述本项目将使用一种特殊的高分辨率电子显微镜直接监测固体导电聚合物(也称为“合成金属”)从液体溶液中的形成，这种显微镜可以在结晶过程发生时直接观察它。这些有机材料被用于许多先进的应用，包括柔性电池、太阳能电池和生物医学设备。然而，它们的复杂结构实际上是如何在分子水平上形成的，科学上还没有很好的理解。该项目将研究这些复杂材料在电化学反应中的形成和生长。这些实验将使用一个特殊的样品台，这将使人们能够在电子显微镜内观察和监控材料从液体变成固体时发生的事情。该研究项目将教授材料科学和工程专业的学生如何对电活性聚合物的微观结构和性能之间的关系建立详细的理解，并为他们更广泛的跨学科教育做出贡献。第二部分：技术综述本研究项目将利用原位透射电子显微镜(TEM)研究功能化聚噻吩膜的电化学沉积。共轭聚(噻吩类)化合物，包括聚(3，4-乙二氧基噻吩基)(PEDOT)和聚(3，4-亚丙基二氧基噻吩基)(PProDOT)，具有重要的科学和商业价值，但其具体的电化学沉积机理尚不清楚。现场样品保持器将用来在透射电子显微镜中直接研究从液体单体溶液到固体聚合物的沉积。这些实验将使监测电极-电解液界面区域的噻吩类单体的氧化聚合成为可能，提供有关所得聚合物膜的结构随输送到电极的总电荷的函数的详细信息。结果将与使用阻抗谱和循环伏安法测量电荷传输性质相关联。还将与通过光学和扫描电子显微镜等互补成像技术获得的图像进行关联。

PART 1: NON-TECHNICAL SUMMARY This project will directly monitor the formation of solid electrically conducted polymers (also known as "synthetic metals") from liquid solutions using a special high-resolution electron microscope which allows direct observation of the cyrstallization process as it takes place. These organic materials are used in many advanced applications including flexible batteries, solar cells, and biomedical devices. However, the way their complicated structures actually form at the molecular level is not well understood scientifically. The project will examine the formation and growth of these complex materials during an electrochemical reaction. The experiments will use a special sample stage that will make it possible to watch and monitor within the electron microscope what happens as the materials change from liquid to solid. The research project will teach students in materials science and engineering how to establish a detailed understanding about the relationship between microstructure and properties of electrically active polymers, as well as contribute to their broader interdisciplinary education. PART 2: TECHNICAL SUMMARY This research project will investigate the electrochemical deposition of functionalized poly(thiophenes) using in-situ transmission electron microscopy (TEM). Conjugated poly(thiophenes), including poly(3,4-ethylenedioxythiophene) (PEDOT) and poly(3,4-propylenedioxythiophene) (PProDOT), are of considerable scientific and commercial interest, but the detailed mechanisms of electrochemical deposition are not yet known. An in-situ sample holder will be used to examine the deposition from liquid monomer solution to solid polymer directly in a TEM. These experiments will make it possible to monitor the oxidative polymerization of thiophene monomers in the region of the electrode-electrolyte interface, providing detailed information about the structural evolution of the resulting polymer films as a function of total charge delivered to the electrode. The results will be correlated with measurements of charge transport properties using impedance spectroscopy and cyclic voltammetry. Correlations will also be made with images obtained by complementary imaging techniques including optical and scanning electron microscopy.