BRIGE - Liquid-phase nanotechnology: Dispersion, rheology, and applications of pristine graphene

1032330绿色单层石墨，即石墨烯，近年来因其优异的机械、热和电性能（包括几种不寻常的量子效应的能力）而成为革命性的新型纳米材料。石墨烯作为新型多功能材料的基础显示出巨大的前景，包括场效应晶体管、柔性电子产品、透明薄膜、纳米复合填料和结构碳纤维。许多这些材料和设备需要可扩展的液相处理。然而，此类材料的开发受到与每个加工步骤相关的基本科学挑战的阻碍：(1) 由于石墨烯片剥离不良和快速重新聚集而导致难以分散，(2) 填料和基体之间的界面粘附力差，(3) 对批量加工的了解不足，特别是在石墨烯流变学和微观结构方面。 先前的研究使用了化学改性的石墨烯，其性能远不如原始石墨烯。 该计划的目标是克服原始石墨烯基材料的这些加工挑战。我们通过石墨烯表面的局部聚合生成了封装在聚合物纳米涂层中的原始石墨烯片，正如成功的初步原理验证实验所证明的那样。该技术可实现抗聚集的稳定性，并将通过有效掺入聚合物纳米复合材料来证明。我们还在石墨烯流变学的新领域进行创新研究，以实现受控的石墨烯加工。 我们将实验流变结果与盘状溶液的微观结构流变学模型的模拟进行比较。 初步模拟结果显示了对排列动力学建模的有希望的结果。智力价值：这一变革性工程计划满足了石墨烯界的三个关键科学挑战。新型界面聚合技术的产生是为了（1）生产可再分散的原始石墨烯，这是以前从未实现过的。此外，聚合物涂层允许（2）对纳米复合材料中石墨烯和聚合物基体之间的界面进行精确设计，以提高界面强度。这种方法具有开创性，因为它避免了与常用氧化石墨加工路线相关的性能下降。该项目还开创了（3）石墨烯流变学的新领域，并通过实验和计算研究的结合，将流变特性与石墨烯排列和分散质量相关联。更广泛的影响：虽然该项目侧重于石墨烯分散、界面化学和流变学的基础知识，但这些发现可立即应用于需要批量液相处理的各种基于石墨烯的材料和设备，包括电子设备、复合材料和薄膜。因此，这个跨学科项目将基础科学研究与实际工程应用结合起来。研究结果将通过演讲和出版物在广泛范围内传播，并通过 PI 的功能材料课程在地方范围内传播。 扩大参与：该计划旨在通过让本科生研究人员和一名高中教师在工作模拟方面的问题设计和可视化中发挥核心作用，将研究和教育结合起来。为了配合这些研究工作，PI 和高中教师将与 TTU T-STEM 中心合作，创建、评估、现场测试和传播纳米技术课程，用于 9-12 年级的 STEM 教育。该课程利用纳米技术中的科学和伦理挑战作为学生主导的研究项目和辩论的平台。该课程将强调学生的探究和主动学习，以便提供更深入的调查和学习，并提高代表性不足群体对 STEM 领域的兴趣。该课程强调纳米技术在环境责任和社会正义方面的潜力（例如发展中国家的石油泄漏清理、水净化），从而在 STEM 领域创造新的动力和热情；这些主题在 STEM 教育中经常被忽视，并且会吸引更广泛的学生背景。

1032330GreenSingle-layer graphite, known as graphene, has taken center-stage as a revolutionary new nanomaterial in recent years due to its excellent mechanical, thermal, and electrical properties, including the capability for several unusual quantum effects. Graphene shows great promise as the basis for novel multifunctional materials, including field effect transistors, flexible electronics, transparent thin films, nanocomposite fillers, and structural carbon fiber. Many of these materials and devices require scalable, liquid-phase processing. However, development of such materials has been hampered by fundamental scientific challenges associated with each processing step (1) Difficult dispersion due to poor exfoliation and rapid re-aggregation of graphene sheets, (2) poor interfacial adhesion between filler and matrix, (3) poor understanding of bulk processing, particularly in regard to graphene rheology and microstructure. Prior studies have utilized chemically modified graphene with properties far inferior to pristine graphene. The goal of this program is to overcome these processing challenges for pristine graphene-based materials. We generate pristine graphene sheets encapsulated in a polymer nano-coating through localized polymerization on the graphene surface, as demonstrated through successful preliminary proof-of-principle experiments. This technique results in stabilization against aggregation and will be demonstrated by effective incorporation into polymer nanocomposites. We also create innovative studies in the novel field of graphene rheology in order to enable controlled graphene processing. We compare experimental rheometric results against simulations of the microstructure-rheology model for discotic solutions. Preliminary simulation results show promising results for modeling alignment dynamics.Intellectual merit: This transformative engineering plan meets three critical scientific challenges in the graphene community. Novel interfacial polymerization techniques are generated for (1) the production of re-dispersible, pristine graphene, which has never been attained before. Furthermore, polymer coating allows (2) the precise engineering of the interface between graphene and the polymer matrix in nanocomposites to increase interfacial strength. This approach is groundbreaking because it avoids the degraded properties associated with the commonly-used graphite oxide processing route. This program also pioneers the novel field of (3) graphene rheology and correlates rheological properties with graphene alignment and dispersion quality through a combination of experimental and computational studies.Broader impacts: Although this program focuses on the fundamentals of graphene dispersion, interfacial chemistry, and rheology, these findings have immediate application to the wide range of graphene-based materials and devices in need of bulk liquid-phase processing, including electronic devices, composites, and films. Thus, this interdisciplinary program combines fundamental scientific research with practical engineering applications. The findings will be disseminated on the broad scale through presentations and publications and on the local scale through the PI's functional materials course.Broadening Participation: The program seeks to integrate research and education by engaging undergraduate researchers and a high-school teacher with a central role in problem design and visualization for the simulation aspects of the work. In concert with these research efforts, the PI and the high school teacher will partner with the TTU T-STEM Center to create, evaluate, field-test, and disseminate nanotechnology curriculum for use in STEM education for grades 9-12. The curriculum uses both scientific and ethical challenges in nanotechnology as a platform for student-driven research projects and debates. This curriculum will emphasize student inquiry and active learning in order to provide deeper investigation and learning and generate increased interest in STEM fields among underrepresented groups. This curriculum creates new motivation and enthusiasm in STEM fields by emphasizing the potential for nanotechnology to be used for environmental responsibility and social justice (e.g., oil spill clean-up, water purification in developing countries); such topics are often neglected in STEM education and will engage a broader spectrum of student backgrounds.