COLLABORATIVE RESEARCH: ELECTRON TRANSPORT MEMBRANE USING NANOSTRUCTURED BLOCK COPOLYMER ASSEMBLIES

智能优点：共轭(导电)聚合物的纳米控制尤其重要，因为此类功能材料的形态对器件性能有重要影响，影响导电性、热稳定性、加工性和机械完整性等性能。这项提议的目标是为有机电子器件创造新的聚合物网络材料，由于形成了定义良好的连续纳米级导电路径，从而提高了性能。这一目标将通过将近单分散导电聚合物(区域规则聚(3-烷基噻吩基)S(rr-P3AT)S)的合成与嵌段共聚物(BCP)的自然自组装相结合来实现，以创造能够形成多个连续组装的新型聚合物材料。这项提议有两个具体目标。首先，将合成含有导电嵌段的新型网状结构的ABC三嵌段共聚物。这些材料的设计将使它们包含产生界面曲率和马鞍面所需的嵌段共聚体积分数，这是纳米网络的标志。此外，聚合物的化学连接性将被设计为限制导电(棒)块的结晶，以保持网络形态。接下来，膜结构将通过散射、显微镜和机械分析技术进行表征；膜的导电性(和迁移率)也将使用四点探针测量和介电光谱分析来检测。与层状和柱状沟道相比，所提出的纳米尺度网络形态具有优越的力学属性，它们的渗透互连区域和大的界面面积为制造具有定制的传输、化学和机械性能的导电材料提供了机会。这些因素将导致聚合物共混系统的显著改进，在聚合物共混系统中，为导电和传输创建统一尺寸的连续路径是提高聚合物器件效率的关键障碍。广泛影响：在有机薄膜中创建连续纳米级导电路径的能力对于有机材料的进一步开发和使用至关重要，因为在磁区边界处较差的电子性能通常会限制整体器件性能。这对发光二极管(LED)、薄膜晶体管(TFT)和光伏(PV)尤其令人担忧，在这些器件的电子活性层中，改善传输是必不可少的。虽然文献中已经报道了rr-P3AT BCP的合成，但本工作试图创新它们的设计。具体地说，上述共聚物将包含一个赋予韧性的嵌段；第二个提供可结晶嵌段的限制的嵌段；以及第三个可结晶和导电的嵌段。这项工作的一个新方面是，对导电rr-P3AT嵌段的化学结构进行了修改，以降低结晶温度，因此结晶不会改变整个自组装嵌段共聚物的结构。提出的研究将为棒状线圈嵌段共聚物的组成、形态和电子性质之间的相互作用提供新的见解。总而言之，这有望导致CP形态和电子性质的优化。此外，这一跨学科项目将培训研究生和本科生，以应对纳米技术方面的关键科学和工程挑战。具体的、更广泛的影响和教育倡议的重点是增加代表性不足群体的参与。这些措施包括：通过PI参与ACS多元化合作伙伴计划和少数族裔学者计划，提供暑期研究和指导机会。此外，联合PI参与了爱荷华州立大学的几个项目(AGEP、新生荣誉和NOBCChE)，将用于从代表性不足的群体中招收研究生到ISU。最后，我们建议在特拉华大学化学工程系和ISU化学系之间进行学生交流，以拓宽他们的研究知识基础。

0930986EppsIntellectual Merit: Nanoscale control of conjugated (conducting) polymers is especially important as the morphology of such functional materials plays a significant role in device performance, influencing properties such as conductivity, thermal stability, processability, and mechanical integrity. The goal of this proposal is to create new polymeric network materials for organic electronics devices, with improved performance due to the formation of well defined and continuous nanoscale conducting pathways. This goal will be achieved by combining the synthesis of near monodisperse conducting polymers (regioregular poly(3-alkylthiophenes) (rr-P3AT)s ), with the natural self assembly of block copolymers (BCPs) to create novel polymeric materials with the ability to form multiply continuous assemblies. There are two specific aims of this proposal. First, novel network forming ABC triblock copolymers containing an electrically conductive block will be synthesized. These materials will be designed such that they contain the block copolymer volume fractions necessary to generate the interfacial curvature and saddle surfaces, which are a hallmark of nanoscale networks. In addition, the chemical connectivity of the polymer will be designed such that crystallization of the conducting (rod) block is confined in order to maintain the network morphology. Next, membrane structures will be characterized by scattering, microscopy, and mechanical analysis techniques; membrane conductivity (and mobility) also will be examined using four point probe measurements, and dielectric spectroscopy. The proposed nanoscale network morphologies have superior mechanical attributes, relative to layers and cylindrical channels, and their percolating interconnected domains and large interfacial area present the opportunity to create conducting materials with tailored transport, chemical, and mechanical properties. These factors will lead to a dramatic improvement over polymer blend systems, where the creation of uniform-sized continuous pathways for conduction and transport is a key hurdle to improving the efficiency of polymeric devices.Broader Impact: The ability to create continuous nanoscale conducting pathways in organic thin films is crucial for further development and use of organic materials because poor electronic properties at domain boundaries often limit overall device properties. This is of particular concern for light emitting diodes (LEDs), thin-film transistors (TFTs), and photovoltaics (PVs), where improved transport is essential in the electronically active layers of these devices. While the synthesis of rr-P3AT BCPs has been reported in the literature, this work seeks to innovate their design. Specifically, the copolymers described above will contain one block that imparts toughness; a second block to provide confinement of the crystallizable block; and a third block that is crystallizable and conducting. A novel aspect of this work is that the chemistry of the conducting rr-P3AT block has been modified to lower the crystallization temperature, so that crystallization does not alter the overall self assembled block copolymer structure. The proposed research will provide new insights into the interplay between rod coil block copolymer composition, morphology and electronic properties. Collectively, this is expected to result in the optimization of CP morphology and electronic properties. Furthermore, this interdisciplinary project will train graduate and undergraduate students to address key scientific and engineering challenges in nanotechnology. Specific broader impact and educational initiatives are focused on increasing the participation of under represented groups. These include: providing summer research and mentorship opportunities through the PI's involvement with the ACS Diversity Partner Program and Minority Scholars Program. Additionally, the co-PI's involvement with several programs at Iowa State University [ISU] (AGEP, Freshman Honors, and NOBCChE) will be used to recruit graduate students from under represented groups to ISU. Finally, we propose the exchange of students between the University of Delaware, Chemical Engineering Department, and the ISU, Department of Chemistry, to broaden their research knowledge base.