Ionoelastomer heterojunctions at the micro- and nano-scale

非技术总结：软聚合物网络可以通过离子的运动传导电流，为开发新型材料和设备提供了潜力。最近的工作集中在当一种携带固定正离子（因此是移动负离子）的材料与另一种携带固定负离子（和移动正离子）的材料接触时形成的界面上。这种接口的作用很像现代电子设备中的电子门，它允许电流在一个方向上通过，但不允许在另一个方向上通过。然而，基于软离子导电聚合物的界面提供了其他有趣的特性，例如在施加小电压时可逆粘附和释放的能力，以及在机械变形时产生电流的能力。该项目旨在加深我们对这类新兴材料的理解，从而为用它们制造新型设备打开大门。为此，它将开发一个离子导电聚合物库，并描述所得界面的行为如何取决于聚合物特性。它将深入了解这些带相反电荷的聚合物混合或不混合的趋势，并利用这些知识来设计自发组装成结的系统，从而提高性能。该项目将为从高中到博士后水平的学生和研究人员提供培训和指导的机会，并将与附近的高中和科罗拉多大学博尔德分校的几个组织合作，吸引、招募和留住不同的参与者群体。技术概述：由离子液体单体或“离子弹性体”形成的具有低玻璃化转变温度的聚电解质交联网络，最近成为一类有前途的软离子导体。虽然最近的研究表明，聚阴离子和聚阳离子材料之间的异质结可以作为固有的可拉伸离子二极管，使晶体管、低压电粘合剂和机电换能器的形成成为可能，但关于它们的操作仍有很多有待了解。该项目将建立一个共聚物库，这些共聚物具有不同含量的不同离子电荷载体和不同的主链化学性质，并表征所产生的离子弹性体异质结的行为如何依赖于这些特征。它将表征聚（离子液体）共混物和嵌段共聚物混合或进行微相或宏观相分离的趋势，以及作为这些参数的函数。最后，它将建立基于自组装和离子种类的光化学模式的路线，以产生高表面积的纳米和微尺度异质结，为所得器件的性能提供潜在的显着改进。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:Soft polymer networks that can conduct currents through motion of ionic species hold potential for the development of new classes of materials and devices. Recent work has focused on the interface formed when one material bearing fixed positive (and therefore mobile negative) ions is placed in contact with another bearing fixed negative (and mobile positive) ions. Such interfaces act much like the electronic gates found in modern electronic devices, which allow current to pass in one direction, but not the other. However, interfaces based on soft ion-conducting polymers offer other interesting properties, such as the ability to reversibly stick and release with the application of a small voltage, and the ability to generate currents when mechanically deformed. This project seeks to deepen our understanding of this emerging class of materials, and to thereby open the door to new types of devices built from them. To do so, it will develop a library of ion-conducting polymers and characterize how the behavior of the resulting interfaces depends on the polymer characteristics. It will provide insight into the tendency of these oppositely charged polymers to mix, or not mix, and use this knowledge to engineer systems that spontaneously assemble into junctions with improved performance. The project will provide opportunities for training and mentoring of students and researchers from the high school to post-doctoral levels, and will partner with nearby high schools and several organizations at the University of Colorado Boulder to engage, recruit, and retain a diverse group of participants.TECHNICAL SUMMARY:Crosslinked networks of polyelectrolytes with low glass transition temperatures formed from ionic liquid monomers, or ‘ionoelastomers’, have recently emerged as a promising class of soft ion conductors. While recent work has shown that heterojunctions between polyanionic and polycationic materials serve as inherently stretchable ionic diodes, enabling the formation of transistors, low-voltage electroadhesives, and electro-mechanical transducers, much remains to be understood about their operation. This project will establish a library of copolymers with varying content of different ionic charge carriers and different backbone chemistries, and characterize how the behavior of the resulting ionoelastomer heterojunctions depends on these characteristics. It will characterize the tendency of poly(ionic liquid) blends and block copolymers to mix, or undergo micro- or macro-phase separation, as a function of these parameters as well. Finally, it will establish routes based on self-assembly and photochemical patterning of ionic species to yield high surface area nano- and micro-scale heterojunctions, offering potentially dramatic improvements in the performance of the resulting devices. .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.