Ion Beam Linking and Ion Beam Welding of Continuously Pulled Carbon Nanotube Yarns

在本研究中，我们研究了离子束焊接对碳纳米管丝结构和性能变化的影响。这项研究的方法将是通过从自对准的纳米管阵列连续拉出碳纳米管纱线，并利用空气中的离子束立即照射纱线。关键是利用离子轰击在管间引入位移作为管间的稳定接触，或局部焊接两个连接的碳纳米管的结合处，以增强管间的导电、声子输运和管内滑动摩擦。离子束处理的纱线有望具有显著的热、电和机械性能。用电子显微镜、拉曼光谱、拉伸测试、电阻和热传导实验对离子辐照效应进行了表征。这项研究包括多尺度建模，以揭示离子辐照产生的缺陷演化的原子尺度细节，随后的结构松弛如何导致稳定的缺陷组态，以及缺陷如何影响与实验相联系的空间和时间尺度上的各种性质。如果成功，这项研究的好处将包括开发一种工业就绪的离子束技术，用于制造高强度和导电性的纱线或绳索。该技术可推广到其他非碳系统，用于恶劣环境下的材料应用。该项目还将对其教育计划产生广泛影响，以增加少数族裔学生的参与，开发课程，并创建电子学习资源，以促进在纳米技术前沿的公共学习。研究活动将与德克萨斯农工大学现有的本科生研究奖学金计划和教师工程丰富经验计划相结合，以促进本科生和高中教师的参与。

In this research, we study the effects of ion beam welding on structural and property changes of carbon nanotube yarn. The approach of this research will be creating carbon nanotube yarn by continuous pulling from self-aligned nanotube arrays, and immediately irradiating the yarn by using an ion beam in air. The key is to use ion bombardment to introduce inter-tube displacements as stable contacts between tubes or to locally weld the junction of two joining carbon nanotubes, in order to enhance inter-tube electrical conduction, phonon transport and tube sliding friction. Ion beam treated yarns are expected to have significantly enhanced thermal, electrical and mechanical properties. The ion irradiation effects are characterized by using electron microscopy, Raman spectroscopy, tensile testing, electrical resistance and heat conduction experiments. This research includes multi-scale modeling to reveal atomic-scale details of evolution of defects created by ion irradiation, how subsequent structural relaxation leads to stable defect configurations, and how defects influence various properties at spatial and temporal scales linkable to experiments. If successful, the benefits of this research will include development of an industry-ready ion beam technique for creation of yarns or ropes of high strength and conductivity. The technique can be extended to other non-carbon systems for materials applications under harsh environments. The project will also have broad impact with its educational plans to increase minority student participation, develop curricula, and create e-learning resources to promote public learning in frontiers of nanotechnology. The research activities will be integrated with existing Undergraduate Student Research Scholar Program and Enrichment Experience in Engineering for Teachers Program at the Texas A&M University to promote undergraduate student and high school teacher participation.