Ionoelastomer heterojunctions at the micro- and nano-scale

非技术综述：软聚合物网络可以通过离子物种的运动传导电流，具有开发新类型材料和器件的潜力。最近的工作主要集中在一种含有固定正离子(因此也就是移动负离子)的材料与另一种含有固定负离子(和移动正离子)的材料接触时形成的界面。这种接口的作用很像现代电子设备中的电子门，允许电流向一个方向流动，但不允许向另一个方向流动。然而，基于软离子导电聚合物的界面还提供了其他有趣的特性，例如在小电压下可逆地粘合和释放的能力，以及在机械变形时产生电流的能力。这个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。为了做到这一点，它将开发一个离子导电聚合物库，并表征所产生的界面的行为如何取决于聚合物的特性。它将提供对这些相反电荷聚合物混合或不混合的趋势的洞察，并利用这一知识来设计自发组装成具有更高性能的结点的系统。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博尔德大学的几个组织合作，以吸引、招募和留住不同的参与者群体。技术摘要：由离子液体单体形成的具有低玻璃化转变温度的聚电解质交联网，或称离子弹性体，最近已成为一类很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作为固有的可伸展离子二极管，使得晶体管、低压电粘剂和机电换能器的形成成为可能，但关于它们的操作仍有许多需要了解的地方。该项目将建立不同离子电荷载体和不同主链化学成分含量不同的共聚物库，并表征由此产生的离子弹性体异质结的行为如何取决于这些特征。它将表征聚(离子液体)共混物和嵌段共聚物的混合趋势，或经历微观或宏观相分离，作为这些参数的函数。最后，它将建立基于离子物种的自组装和光化学图案化的路线，以产生高比表面积的纳米和微米级异质结，从而潜在地显著提高所产生的器件的性能。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: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.