GOALI: Nanomanufacturing of Ultrahigh-Performance Continuous Carbon Nanofibers and Their Assemblies

与其他纳米材料相比，连续碳纳米纤维在成本、易于处理、加工成有用的应用以及将其集成到多尺度组装中的可能性方面具有优势。然而，它们的机械性能需要大幅提高，以改善加工性。由于纳米纤维的尺寸较小，在加工过程中很难或不可能使用已成功用于制造常规较大尺寸碳纤维的外部机械约束。适当地约束纳米纤维可以达到或超过常规纤维的机械性能；高的机械性能与低成本的加工、小直径和超高的表面积相结合，将开辟纳米纤维应用的广阔新领域。这一学术联系机会(GOALI)项目奖支持基础研究，为开发利用内部约束的替代方法提供必要的知识。与仅适用于定向(一维)光纤丝束的经典外部约束不同，新工艺将同时适用于一维以及二维和三维纳米纤维结构，这将导致革命性的负担得起的高性能块状纳米结构碳产品。这些多尺度纳米纤维结构可广泛应用于航空航天、能源、环境保护、医疗保健、生物医学和汽车工业。因此，这项研究的结果将有利于美国的经济和社会。这项研究涉及多个学科，包括制造、电动力学、过程控制和材料科学。多学科的方法和与两家公司的合作将有助于扩大未被充分代表的群体在研究中的参与，并对工程教育产生积极影响。该项目在纳米纤维制造过程中的内部约束概念可以克服传统碳纤维高机械性能所需的经典外部机械约束的问题。然而，要实现碳纳米纤维，还需要解决几个科学障碍？充分发挥潜力。本研究将研究在纳米纤维制备的三个阶段，即纳米纤维前驱体的静电纺丝、纳米纤维的氧化稳定和高温碳化过程中，由于添加少量的约束性纳米夹杂物(如碳纳米管)而导致纳米纤维结构形成的机理。研究小组将进行广泛的参数研究，以分析加工-结构-性能的关系，并为单个纳米纤维及其排列的一维组件选择最佳加工参数。然后，我们将探讨这些参数在纳米制造、二维和三维宏观碳纳米纤维结构中的适用性。学术研究人员与两家公司的合作将有助于将这一基础研究集中在实际问题上，并将加快纳米制造的规模。

Continuous carbon nanofibers have advantages over other nanomaterials in terms of cost, ease of handling, processing into useful applications, and possibility of their integration into multi-scale assemblies. However, their mechanical properties need to be substantially improved to improve processability. Due to the small scale of the nanofibers, it is difficult or impossible to use external mechanical constraints during processing that have been successfully utilized in manufacturing conventional larger-scale carbon fibers. Properly constrained nanofibers can match or exceed mechanical properties of conventional fibers; high mechanical performance coupled with low cost processing, small diameter, and ultrahigh surface area will open up broad new areas of nanofiber applications. This Grant Opportunity for Academic Liaison with Industry (GOALI) Program award supports fundamental research to provide needed knowledge for the development of an alternative approach utilizing internal constraints. Unlike the classical external constraint that is only applicable to aligned (one-dimensional) fiber tows, the new process will be applicable to both one-dimensional and two- and three-dimensional nanofiber constructs that can lead to revolutionary affordable high-performance bulk nanostructured carbon products. These multi-scale nanofilamentary structures can be used in a broad range of applications in aerospace, energy, environmental protection, healthcare, biomedical, and automotive industries. Therefore, results from this research will benefit the U.S. economy and society. This research involves several disciplines including manufacturing, electrodynamics process control, and materials science. The multi-disciplinary approach and collaboration with two companies will help broaden participation of underrepresented groups in research and positively impact engineering education.This project's concept of internal constraint during nanomanufacturing of nanofibers can overcome the issues with the classical external mechanical constraint that is instrumental for high mechanical properties of conventional carbon fibers. However, several scientific barriers still need to be resolved to achieve carbon nanofibers? full potential. This research will study the mechanisms of nanofiber structure formation as a result of addition of small quantities of constraining nano-scale inclusions such as carbon nanotubes in all three stages of nanofiber manufacturing, i.e. electrospinning of nanofiber precursors, their oxidative stabilization, and high-temperature carbonization. The research team will perform extensive parametric studies to analyze processing-structure-properties relationships and to select optimal processing parameters for individual nanofibers and their aligned one-dimensional assemblies. Applicability of these parameters to nanomanufacture two- and three- dimensional macroscopic carbon nanofiber constructs in an integrated process will be then explored. The partnership of academic researchers with two companies will help focus this fundamental research on practical issues and will accelerate nanomanufacturing scale-up.