Modeling the Auxetic Transition for Carbon Nanotube Sheets

• Published in: arXiv.org
• Main Authors: Coluci, Vitor R, Hall, Lee J, Kozlov, Mikhail E, Zhang, Mei, Dantas, Socrates O, Galvao, Douglas S, Baughman, Ray H
• Format: Paper Journal Article
• Language: English
• Published: Ithaca Cornell University Library, arXiv.org 17.03.2009
• Subjects: Carbon; Elongation; Mathematical models; Mechanical properties; Multi wall carbon nanotubes; Nanotubes; Physics - Materials Science; Sheets; Single wall carbon nanotubes
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.0903.2892

A simple model is developed to predict the complex mechanical properties of carbon nanotube sheets (buckypaper) [Hall \textit{et al.}, \textit{Science} \textbf{320} 504 (2008)]. Fabricated using a similar method to that deployed for making writing paper, these buckypapers can have in-plane Poisson's ratios changed from positive to negative, becoming auxetic, as multiwalled carbon nanotubes are increasingly mixed with single-walled carbon nanotubes. Essential structural features of the buckypapers are incorporated into the model: isotropic in-plane mechanical properties, nanotubes preferentially oriented in the sheet plane, and freedom to undergo stress-induced elongation by both angle and length changes. The expressions derived for the Poisson's ratios enabled quantitative prediction of both observed properties and remarkable new properties obtainable by structural modification.