Speaker
Description
Interconnected networks of carbon nanotubes (CNT) synthesized by the direct Floating Catalyst CVD process (FCCVD) are the key structural components in macroscopic ensembles, such as CNT yarns and fabrics used in composite engineering and damage-tolerant multifunctional structures.
Measuring the tensile properties of CNT bundles (i.e., building blocks of the nanostructured network) yet remains a challenge because of their length (millimetre-long), intrinsic entanglement and merging at the aerogel-state, the lack and/or technical complexity of testing methods for such small objects. Besides, FCCVD produces inherently polydispersed samples in terms of the CNT diameter and number of layers, leading to the coexistence of predominantly round, elliptical and radially collapsed CNTs in the bundles, depending on the synthesis conditions. Our recent study based on transversal TEM of FIB-milled macroscopic fibres demonstrated the importance of CNT bundling and provided the first means for the identification and quantitative analysis of collapsed CNTs and their packing efficiency in the bundles. The planar collapsed tubes form the stacks, which improves shear interactions between adjacent tubes and has an implication on inter-tube slippage and the tensile failure in shear for macroscopic CNT fibres.
With this knowledge, we correlate the mechanical performance of the nanostructured objects (bundles of different populations and packing of CNTs) with the bulk properties of macroscopic materials (CNT fibres and fabrics). This complex approach includes the development of nanomechanical tests of individualized CNT bundles coupled with in situ TEM and/or Raman spectroscopy, which then supplemented with micromechanical analysis of CNT aerogel filaments with in situ SAXS and WAXS to explain the CNT network alignment and progressive sliding at tensile deformation, in order to provide general guidelines for the manufacturing of strong yarns and fabrics.
| Speaker Country | Spain |
|---|