Carboxyl-alkyl Functionalization for Sustainable Mixed Conduction Polymers: molecular design and mechanistic insights

非技术总结：聚合物（塑料）可以传导电子和离子电荷，有望成为从环境和电生理传感器到能量存储等应用的核心构建模块。这种混合导电聚合物的主要优点包括其灵活的外形因素，它们能够在低温下使用喷墨或丝网印刷等增材印刷方法进行加工，以及它们的多功能技术能力。通过对分子结构的明智选择，也有可能获得水溶性聚合物，从而为一系列传感、高级计算和能源应用开发环境友好的选择。该项目旨在发现新的、可持续的混合导电聚合物化学和工艺，并确定关键的结构-功能关系。它将通过化学设计和合成、分子和结构表征、性质确定和优化以及通过综合理论和实验方法来实现这一目标。因此，新一代的混合导电聚合物具有前所未有的性能可能被确定。参与该计划的学生将受益于该计划的多学科性质，在与其他领域的科学家和工程师沟通和合作的能力的平衡中发展技术专长。共同pi致力于指导不同群体的研究生和本科生研究人员，并参与K-12学生外展计划，以加速代表性不足群体对STEM的兴趣。技术概述：共轭聚合物半导体通过电解质离子渗透进行电化学诱导掺杂，有望成为从环境和电生理传感器到发光电化学电池、神经形态模块和能量存储等应用的核心构建模块。这类聚合物被称为有机混合离子-电子导体（OMIECs），其特征被认为源于离子带电或极性侧链，易于溶剂化或与离子相互作用。迄今为止，OMIEC化学物质的选择受到严重限制，因此从头开始设计的转型进步需要对有利的合成可及分子结构和薄膜形态有更深入的了解，这些结构和薄膜形态可以实现前所未有的离子-电子耦合水平，与电化学掺杂的兼容性以及离子渗透效应。为了解决材料设计和OMIEC中传输现象的局限性，该项目包括以下三个目标：(i)合成和表征未探索的侧链和主链范式的目标OMIEC结构；（ii）通过operando研究和分子模型建立OMIEC主链和侧链化学与电解质门控、膜膨胀和离子/电子传输特性之间的联系；（iii）探索混合侧链化学（通过共聚和/或共混）作为对OMIEC性能进行额外控制的途径。据推测，通过新的侧链化学来扩展OMIEC材料的设计空间，包括通过共聚和共混加入的额外设计能力，可以实现对OMIEC性能和设备性能的前所未有的控制。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

NON-TECHNICAL SUMMARY:Polymers (plastics) that can conduct both electronic and ionic charge promise to serve as central building blocks for applications ranging from environmental and electrophysiological sensors to energy storage. Key advantages of such mixed conduction polymers include their flexible form factor, their ability to be processed at low temperatures using additive printing approaches such as inkjet or screen printing, and their multifunctional technological capabilities. Through judicious choice of molecular structures, it is also possible to access water-soluble polymers that will enable development of environmentally benign options for a range of sensing, advanced computing, and energy applications. This project aims toward the discovery of new, sustainable mixed conduction polymer chemistries and processes and identify critical structure-function relationships. It will do so through a combination of chemical design and synthesis, molecular and structural characterization, property determination and optimization, as well as through an integrated theoretical and experimental approach. As a result, new generations of mixed conduction polymers having unprecedented performance may be identified. Students engaged in the proposed project will benefit from the multidisciplinary nature of the program, developing technical expertise in balance with the ability to communicate and collaborate with scientists and engineers in other fields. The co-PIs are committed to mentorship of diverse groups of graduate and undergraduate researchers and participation in K-12 student outreach programs to accelerate interest in STEM in underrepresented groups. TECHNICAL SUMMARY:Conjugated polymer semiconductors that undergo electrochemically induced doping through permeation of ions from an electrolyte promise to serve as central building blocks for applications ranging from environmental and electrophysiological sensors to light-emitting electrochemical cells, neuromorphic modules, and energy storage. Known as organic mixed ionic-electronic conductors (OMIECs), this class of polymers has characteristics believed to originate from ionically charged or polar side chains that readily solvate or interact with ionic species. To date, the choice of OMIEC chemistries is severely limited whereby transformational advancements in ab initio design require much improved fundamental insight into advantageous synthetically accessible molecular structures and thin-film morphologies that could allow for unprecedented levels of ionic-electronic coupling, compatibility with electrochemical doping, and ion percolation effects. To address limitations in materials design and transport phenomena in OMIECs, this project encompasses the following three Aims: (i) synthesize and characterize target OMIEC structures with unexplored side-chain and backbone paradigms; (ii) establish links between OMIEC backbone and side-chain chemistries and electrolyte gating, film swelling, and ion/electron transport properties through operando studies and molecular modeling; and (iii) explore mixed side-chain chemistries (via copolymerization and/or blending) as a route towards additional control over OMIEC properties. It is hypothesized that expanding the design space available to OMIEC materials via new side-chain chemistries, including additional design capabilities incorporated via copolymerization and blending, could enable unprecedented control over OMIEC properties and device performance. .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.