CAREER: Block Polyelectrolyte Complexes for Controlled Mixed Ionic-Electronic Conduction

该项目由DMR聚合物项目和促进竞争研究的既定项目（EPSCoR）共同资助。第1部分：非技术总结在生物界面（即生物电子学）上使用电子材料和设备可以实现在人类健康方面的重要应用，例如电刺激（例如，治疗帕金森病或阿尔茨海默病）、生物传感、神经/伤口愈合和电生理测量。但是，日常设备中最常见的电子产品是由贵金属导体制成的，比如金或铂。这些材料不适合用于与人类健康有关的应用，因为它们太硬、太脆。它们也像生物系统那样使用电子而不是离子进行通信（例如，神经元通过离子浓度的差异进行通信）；这使得很难将电子信号“翻译”为离子信号以进行刺激，反之亦然。为了解决这些问题，需要更柔软、生物相容性更强、能同时传导电子和离子的新材料。这项研究将引入一种新的聚合物，它符合这些标准，并具有受生物学启发的特性。这些电子和离子导电聚合物将被合成、表征并集成到器件中，以提供设计规则来优化专门用于生物电子学应用的电子材料的效率。因此，这项研究将对材料的基础研究和医疗保健中的应用产生影响。它还将提供教育活动、动手演示和指导计划，旨在广泛教育聚合物材料的使用，并激发和培养对材料科学和工程的兴趣。这些教育、推广和研究活动将积极吸引研究生和本科生，帮助他们发展跨学科研究人员的能力，从而也增加边缘化学生的参与和保留。导电聚合物也可以传输离子（即有机混合离子-电子导体），可以作为离子和电子信号之间的换能器，在神经系统疾病的研究和治疗中发挥重要作用。然而，目前用于生物电子应用的功能化这些材料的方法仅限于与添加剂混合和侧链修饰，这通常会降低设备的电子性能。因此，计划研究的目标是获得有机混合离子-电子导体，通过电子绝缘聚合物的功能化来保持或提高其电子性能。为了实现这一目标，中性阴离子二嵌段共聚物和带正电荷的导电聚合物（即嵌段聚电解质复合物）之间的络合作用将被用来控制无序混合导体的有序，并最终为特定的生物电子学应用定制它们的特性。这些嵌段多电解质复合物将模拟生物系统的关键特性，同时精确控制离子和电子输运以及离子-电子耦合的相对贡献。研究将集中于模拟三种生物特性：(1)特异性，(2)动态和适应性，以及(3)生物降解性。这项研究的结果将为生物电子器件（例如，离子选择传感器，可注射和导电组织支架，瞬态器件）提供新的功能，并有助于建立高性能有机混合离子-电子导体的基本分子设计规则。这项研究还将为学生和家长提供关于功能性塑料，特别是塑料电子产品的积极社会影响的教育活动。一个实验模块将被开发，以介绍大三本科生有机电子学的真实研究。该实验室生产的样品将用于K-12学生的塑料电子外联模块。这笔拨款还将支持为有兴趣攻读材料科学与工程大学学位的高中女生建立一个指导和支持网络。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。

This project is jointly funded by the DMR Polymers Program and the Established Program to Stimulate Competitive Research (EPSCoR). PART 1: NON-TECHNICAL SUMMARYThe use of electronic materials and devices at biological interfaces (i.e., bioelectronics) enables important applications in human health, such as for electrostimulation (e.g., to treat Parkinson’s or Alzheimer’s disease), biosensing, nerve/wound healing, and electrophysiological measurements. But, most common electronics in everyday devices are made of precious metal conductors, such as gold or platinum. These materials are not ideal for applications related to human health because they are too rigid and brittle. They also use electrons for communication instead of ions like biological systems do (e.g., neurons communicate through differences in ion concentration); this makes it difficult to “translate” electronic signals to ionic ones for stimulation, or vice versa for sensing. To address these problems, new materials are needed that are much softer, biocompatible, and enable the conduction of both electrons and ions. This research will introduce a new class of polymers that fit these criteria and have properties inspired from biology. These electron- and ion-conducting polymers will be synthesized, characterized and integrated in devices, to provide design rules to optimize the efficiency of electronic materials specifically made for bioelectronics applications. This research will therefore have an impact in both fundamental research on materials and applications in healthcare. It will also provide educational activities, hands-on demonstrations, and a mentoring program designed to broadly educate about the uses of polymeric materials and trigger and nurture interest in materials science and engineering. These educational, outreach, and research activities will actively engage graduate and undergraduate students to help develop their capabilities as interdisciplinary researchers, and thereby also increase the participation and retention of marginalized students.PART 2: TECHNICAL SUMMARYElectrically-conductive polymers that can also transport ions (i.e., organic mixed ionic-electronic conductors) could play a major role in the study and treatment of neurological disorders by acting as transducers between ionic and electronic signals. However, current methods to functionalize these materials for bioelectronic applications have been limited to blending with additives and to side-chain modification, which often decrease the electronic performance of the devices. The goal of the planned research is therefore to access organic mixed ionic-electronic conductors that maintain or improve their electronic performance upon functionalization with an electronically-insulating polymer. To achieve this goal, the complexation between neutral-anionic diblock copolymers and positively-charged conductive polymers (i.e., block polyelectrolyte complexes) will be leveraged to control the ordering of otherwise disordered mixed conductors, and ultimately tailor their properties for applications specific to bioelectronics. These block polyelectrolyte complexes will mimic key properties of biological systems while precisely controlling the relative contribution of ionic and electronic transport and ionic-electronic coupling. The research will focus on mimicking three biological properties: (1) specificity, (2) dynamic and adaptable properties, and (3) biodegradability. The results of this research will enable new functionalities for bioelectronic devices (e.g., ion-selective sensors, injectable and conductive tissue scaffolds, and transient devices), and contribute to the establishment of fundamental molecular design rules for high performance organic mixed ionic-electronic conductors. This research will also integrate educational activities for students and parents about the positive societal impact of functional plastics, in particular plastic electronics. A laboratory module will be developed to introduce junior undergraduate students to authentic research in organic electronics. The samples produced during this laboratory will be used in an outreach module on plastic electronics for K-12 students. This grant will also support the creation of a mentoring and support network for high school girls interested in pursuing a college degree in materials science and engineering.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.