title: Key factors limiting carbon nanotube yarn strength: exploring processing-structure-property relationships.
abstract: Studies of carbon nanotube (CNT) based composites have been unable to translate the extraordinary load-bearing capabilities of individual CNTs to macroscale composites such as yarns. A key challenge lies in the lack of understanding of how properties of filaments and interfaces across yarn hierarchical levels govern the properties of macroscale yarns. To provide insight required to enable the development of superior CNT yarns, we investigate the fabrication-structure-mechanical property relationships among CNT yarns prepared by different techniques and employ a Monte Carlo based model to predict upper bounds on their mechanical properties. We study the correlations between different levels of alignment and porosity and yarn strengths up to 2.4 GPa. The uniqueness of this experimentally informed modeling approach is the model's ability to predict when filament rupture or interface sliding dominates yarn failure based on constituent mechanical properties and structural organization observed experimentally. By capturing this transition and predicting the yarn strengths that could be obtained under ideal fabrication conditions, the model provides critical insights to guide future efforts to improve the mechanical performance of CNT yarn systems. This multifaceted study provides a new perspective on CNT yarn design that can serve as a foundation for the development of future composites that effectively exploit the superior mechanical performance of CNTs.
authors.affiliation: Department of Mechanical Engineering, Northwestern University , 2145 Sheridan Road, Evanston, Illinois 60208-3111, United States.
authors.forename: Allison M
authors.initials: AM
authors.lastname: Beese
authors.forename: Xiaoding
authors.initials: X
authors.lastname: Wei
authors.forename: Sourangsu
authors.initials: S
authors.lastname: Sarkar
authors.forename: Rajaprakash
authors.initials: R
authors.lastname: Ramachandramoorthy
authors.forename: Michael R
authors.initials: MR
authors.lastname: Roenbeck
authors.forename: Alexander
authors.initials: A
authors.lastname: Moravsky
authors.forename: Matthew
authors.initials: M
authors.lastname: Ford
authors.forename: Fazel
authors.initials: F
authors.lastname: Yavari
authors.forename: Denis T
authors.initials: DT
authors.lastname: Keane
authors.forename: Raouf O
authors.initials: RO
authors.lastname: Loutfy
authors.forename: SonBinh T
authors.initials: ST
authors.lastname: Nguyen
authors.forename: Horacio D
authors.initials: HD
authors.lastname: Espinosa
keywords: carbon nanotube; hierarchical composites design; multiscale Monte Carlo modeling; processing-structure-property relationships; yarn