211. MECHANICAL PROPERTIES OF MATS OF WELL-ALIGNED MULTI-WALLED CARBON NANOTUBES

Department: NanoEngineering
Research Institute Affiliation: Graduate Program in Materials Science and Engineering
Faculty Advisor(s): Kenneth S. Vecchio

Primary Student
Name: Christian Peter Deck
Email: cdeck@ucsd.edu
Phone: 858-534-0882
Grad Year: 2008

Abstract
Carbon nanotubes (CNTs) have been the subject of great interest in many fields, due to their exceptional mechanical properties and geometry. In this work, the mechanical properties of mats of well-aligned multi-walled CNTs were investigated. A stage was designed and built to allow in-situ scanning electron microscopy observation of compression, tension, and shear testing of densely-packed mats of well-aligned multi-walled CNTs. Force measurements were taken and the elastic modulus of the CNT mats was measured under different testing configurations; modulus values ranged from <1GPa in compression to roughly 35GPa in tension. In addition, other properties such as tube-substrate bond strength and time-dependent responses were investigated. In addition to measuring the modulus of these CNT mats, the flexural rigidity (the product of modulus and moment of inertia) is important to predict the mechanical response of CNTs in deflection and buckling. A method of measuring the flexural rigidity of CNT mats through monitoring their deflection as a function of fluid flow was developed. CNT deflection was correlated with measurements of transmitted laser intensity, where a decrease in intensity with increased fluid velocity was observed as a result of the bending of the CNTs. This flow was simulated based on the Stokes-Oseen equations with a correction for the small length scales associated with nanotube mats, and the fluid drag force exerted on the tubes was found. The experimental data on the deflections and the estimated force on the tubes from simulations are used for determining the flexural rigidity of CNTs, to be of the order of ~10^(-15) Nm^2.

« Back to Posters or Search Results