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

非技术总结：可以传导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建块。这种混合导电聚合物的关键优点包括它们的柔性形状因子， 它们在低温下使用添加剂印刷方法如喷墨或丝网印刷进行加工的能力，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，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，性能测定和优化的组合，以及通过综合的理论和实验方法来实现这一目标。 因此，可以识别具有前所未有的性能的新一代混合导电聚合物。参与该项目的学生将受益于该计划的多学科性质，发展技术专长，并与其他领域的科学家和工程师进行沟通和合作。co-PI致力于指导研究生和本科生研究人员的不同群体，并参与K-12学生推广计划，以加速代表性不足的群体对STEM的兴趣。通过离子从电解质渗透而经历电化学诱导掺杂的共轭聚合物半导体有望用作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的应用的中心构建块。被称为有机混合离子-电子导体（OMIEC）的这类聚合物具有被认为源自容易与离子物质溶剂化或相互作用的带离子电荷或极性侧链的特征。迄今为止，OMIEC化学的选择受到严重限制，由此从头设计中的变革性进步需要对有利的合成可获得的分子结构和薄膜形态的更好的基本见解，这些分子结构和薄膜形态可以允许前所未有的离子-电子耦合水平、与电化学掺杂的兼容性和离子渗透效应。为了解决材料设计和OMIEC中的传输现象的限制，该项目包括以下三个目标：（i）合成和表征具有未探索的侧链和主链范例的目标OMIEC结构;（ii）通过操作研究和分子模拟建立OMIEC主链和侧链化学与电解质门控、膜溶胀和离子/电子传输性质之间的联系;和（iii）探索混合侧链化学（通过共聚和/或共混）作为对OMIEC性质进行额外控制的途径。据推测，通过新的侧链化学物质（包括通过共聚和共混引入的额外设计能力）扩展OMIEC材料可用的设计空间，可以实现对OMIEC性能和器械性能的前所未有的控制。该奖项反映了NSF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.