Mechanical behavior of ultralong multiwalled carbon nanotube mats

Abstract

Carbon nanotubes (CNTs) have been a subject of great interest partially due to their potential for exceptional material properties. Improvements in synthesis methods have facilitated the production of ultralong CNT mats, with lengths in the millimeter range. The increased length of these ultralong mats has, in return, opened the way to greater flexibility to probe their mechanical response. In this work, mats of dense, well-aligned, multiwalled carbon nanotubes were grown with a vapor-phase chemical vapor deposition technique using ferrocene and benzene as reactants, and subsequently tested in both tension and compression using two methods, in a thermomechanical analyzer and in situ inside a scanning electron microscope. In compression, measured stiffness was very low, due to buckling of the nanotubes. In tension, the nanotube mats behaved considerably stiffer; however, they were still more compliant than expected for nanotubes (∼1TPa). Analysis of both the growth method used and the nanotube mat fracture surface suggests that the mats grown in this method are not composed of continuous nanotubes and their strengths actually closely match those of woven nanotube yarns and ropes.

Understanding the nanoscale local buckling behavior of vertically aligned MWCNT arrays with van der Waals interactions

“…Similarly, local periodic buckling regions and stiffness of VACNTs under nano-indentation were reported 4 in a low-cyclic compression. These local buckling behaviors of VACNT were observed in many experiments and there are some research studies 3,5,6,[9][10][11][12][13] which employed the classical Euler's column buckling model 14 with the formula: The periodic buckling waves were observed during electrical conductivity characterization of a VACNT block.…”

Macroscopic Carbon Nanotube Assemblies: Preparation, Properties, and Potential Applications

“…Such remarkable flexibility and resilience of nanotubes potentially make them an ideal low‐weight foamlike material once they are organized into specific 3D architectures, such as aligned 3D arrays or foams. Recent work has demonstrated that vertically aligned MWNT arrays exhibit super‐compressible behavior, in which individual nanotubes act as strong nanoscale struts and the internanotube spaces act as interconnected open‐air cells 121, 122. The compressed nanotubes could be collectively squeezed by buckling and folding themselves like springs.…”

Shock formation and rate effects in impacted carbon nanotube foams

“…have the ability to recover from large strains of up to 80% upon unloading [10,15]. Their deformation response is highly localized and in compression these foams support the formation of sequential buckles, originating from anisotropic, graded functional properties.…”