In-Situ Studies of the Electrochemical Deposition of Functionalized Poly(thiophene) Copolymers

第1部分：非技术总结某些有机“塑料”材料称为共轭聚合物，它们能够以类似于传统金属和半导体的方式导电。这些物质在包括储能、化学传感器和生物医学设备在内的广泛应用中具有相当大的科学和商业价值。然而，这些材料从小分子液体转变为聚合物固体的基本机制还不是很清楚。这种对科学认识的缺乏限制了为特定目的精确定制这些材料的能力。现在有了专门的电子显微镜样品阶段，可以对这些材料的形成进行详细的本地研究，揭示这一复杂过程以前未知的方面。该项目将使用高分辨率电子显微镜和相关分析技术，监测材料从前体液体经过粘性中间体到最终固体共轭聚合物产品时形成的反应产物的局部形状和化学成分。这项工作还将使材料科学和工程的研究生能够获得专门的高级教育，并建立关于使用电化学反应从小分子形成聚合物的新见解。第2部分：技术总结此前已建立的原位、环境控制的电子显微镜样品台可用于使用低剂量透射电子显微镜(TEM)直接监测液体有机单体3，4-乙二氧基噻吩溶液(EDOT)到最终聚(3，4-乙二氧基噻吩基)(PEDOT)共轭聚合物产品的电化学转变过程。然而，关于该过程的许多基本问题仍然未知，包括共聚单体的影响和在反应介质中引入固体纳米颗粒。这项研究项目将量化这些化学和组成变化对沉积过程的影响，特别是当使用更亲水的共聚单体(EDOTacid)时，低聚物液滴的成核、生长和重新溶解回到溶液中。透射电子显微镜实验将得到能够提供与反应相关的化学变化的更多信息的方法的补充，包括光学显微镜、纳米级FTIR/AFM和微聚焦拉曼光谱。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

PART 1: NON-TECHNICAL SUMMARYCertain organic "plastic" materials known as conjugated polymers are able to conduct electrical charge in a manner similar to traditional metals and semiconductors. These substances are of considerable scientific and commercial interest for a wide variety of applications including energy storage, chemical sensors, and biomedical devices. However, the fundamental mechanisms by which these materials transition from small-molecule liquids to polymer solids are not well understood. This lack of scientific understanding limits the ability to precisely tailor these materials for specific purposes. Specialized electron-microscopic sample stages are now available that allow for detailed local studies of the formation of these materials, revealing previously unknown aspects of this complex process. This project will monitor the local shape and chemistry of the reaction products formed as the material proceeds from precursor liquids, through sticky intermediates, to the final solid conjugated polymer products using a high-resolution electron microscope and related analysis techniques. The work will also enable graduate students in materials science and engineering to obtain specialized advanced education and establish new insights about the formation of polymers from small molecules using an electrochemical reaction. PART 2: TECHNICAL SUMMARYIt has been previously established that in-situ, environmentally-controlled electron-microscopic sample stages can be used to directly monitor the electrochemical transition from a solution of liquid organic monomer 3,4-ethylenedioxythiophene (EDOT) to the final poly(3,4-ethylenedioxythiophene) (PEDOT) conjugated polymer product using low-dose transmission electron microscopy (TEM). However many fundamental questions remain unknown about the process, including the influence of comonomers and introduction of solid nanoparticles in the reaction medium. This research project will quantify the influence of these variations in chemistry and composition on the deposition process, particularly the nucleation, growth, and redissolving of oligomer droplets back into solution when using a more hydrophilic co-monomer (EDOTacid). The TEM experiments will be complemented with methods able to provide additional information about the chemical changes associated with the reaction, including optical microscopy, nanoscale FTIR/AFM, and microfocused Raman spectroscopy.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.