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

非技术综述：可以同时进行电子和离子电荷的聚合物(塑料)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件。这种混合导电聚合物的主要优势包括其灵活的外形，能够在低温下使用喷墨或丝网印刷等添加剂印刷方法进行处理，以及它们的多功能技术能力。通过明智地选择分子结构，还可以获得水溶性聚合物，这将使一系列传感、先进计算和能源应用的环境友好选项的开发成为可能。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、性质测定和优化以及综合理论和实验方法来实现这一点。因此，具有前所未有的性能的新一代混合导电聚合物可能被识别出来。参与拟议项目的学生将受益于该项目的多学科性质，在与其他领域的科学家和工程师沟通和合作的能力之间取得平衡，发展技术专业知识。联合PIS致力于指导不同的研究生和本科生研究人员群体，并参与K-12学生外展计划，以促进代表不足的群体对STEM的兴趣。技术概述：共轭聚合物半导体通过从电解液中渗透离子进行电化学诱导掺杂，有望成为环境和电生理传感器、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)，其特征被认为来自于容易溶解离子物种或与离子物种相互作用的带离子或极性侧链。到目前为止，OMIEC化学的选择受到了严重的限制，因此从头计算设计的变革性进步需要对有利的可合成的分子结构和薄膜形貌有更好的基础洞察力，这些结构和薄膜可以实现前所未有的离子-电子耦合、与电化学掺杂的兼容性和离子渗流效应。为了解决OMIEC在材料设计和传输现象方面的局限性，该项目包括以下三个目标：(I)合成和表征具有未知侧链和主链范型的目标OMIEC结构；(Ii)通过操纵性研究和分子模拟，在OMIEC主链和侧链化学与电解液门控、薄膜膨胀和离子/电子传输特性之间建立联系；以及(Iii)探索混合侧链化学(通过共聚和/或混合)作为进一步控制OMIEC性能的途径。假设通过新的侧链化学扩大OMIEC材料的设计空间，包括通过共聚和混合引入的额外设计能力，可以实现对OMIEC性能和器件性能的前所未有的控制。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。

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.