How Do Carbon Nanotube Fibers Gain Their Strength?

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Venue:Academic Health Center 3-205

Abstract:

The potential of translating the superb mechanical and physical properties of individual carbon nanotubes (CNTs) at the nano-scale to the macro-scale of continuous fibers is fascinating and has driven considerable research interest in the past decade. From the viewpoint of reinforcements for fiber composites, the potential for using CNTs in a continuous form would enable their adaptation to many well-developed composites processing, characterization and micromechanics methodologies. Even though very high strengths and moduli for CNT fiber have been reported in the literature, the processing of high performance CNT fibers with consistent, reproducible quality remains elusive. This presentation is intended to introduce our current research, the aims of which are two-fold. First, a concerted effort has been made to assess the status of CNT fiber technology by examining fibers from various sources based on different processing methods. Research results in characterizing the tensile, compressive, torsion, as well as electromechanical behaviors of CNT fibers will be reported. Through our characterization studies, a more comprehensive knowledge-base of CNT fiber has emerged. This research has fueled the question, "How do CNT fibers gain their strength?". Therefore, our second initiative is focused on identifying key contributing factors affecting the mechanical properties of CNT fibers. Preliminary research results based upon the coarse-grained molecular dynamics in modeling the influence of these factors, such as CNT length, CNT entanglement, intertube interactions, as well as the fiber twist angle, will be reported. The combined experimental and analytical effort will eventually enable the optimal design of CNT fibers for high performance composite applications.

Bio:

Dr. Tsu-Wei Chou is the Pierre S. du Pont Chair of Engineering at the University of Delaware. He received the Ph.D. degree in materials science from Stanford University. Dr. Chou's research interests are in materials science, applied mechanics, fiber composite materials, piezoelectric materials, and nanocomposites. He has authored over 330 archival journal papers and book chapters in these areas. He is the author of the book, Microstructural Design of Fiber Composites, Cambridge University Press, England (1992), the co-author of the book, Composite Materials and Their Use in Structures, Elsevier Applied Science, London (1975), and the editor of several books. Dr. Chou is a Fellow of ASME, ASM, ASC, ACerS, TMS and AIAA, and a recipient of the Charles Russ Richards Memorial Award and the Worcester Reed Warner Medal of ASME, the Distinguished Research Award of American Society for Composites, and the Francis Alison Medal as well as the Medal of Excellence in Composite Materials of the University of Delaware. Dr. Chou is the Editor-in-Chief of the international journal Composites Science and Technology. He has been recognized by ISI as one of the "Highly Cited Researchers" in the world. Dr. Chou has been named among top 100 materials scientists (ranked 34th) of the past decade (2000-2010) by Times Higher Education, and is honored as a World Fellow by the International Committee on Composite Materials.