Speaker
Description
Interconnected networks of carbon nanotubes (CNT) synthesized by the direct Floating Catalyst CVD process (FCCVD) are the key structural components in macroscopic yarns and sheets. These macromaterials demonstrate high mechanical and electrical properties relevant to a wide range of applications.
Mechanical testing of CNT macromaterials usually involves dedicated equipment, such as micro- testing machines and stations for in situ experiments. The examples include tensile tests combined with in situ Raman spectroscopy, SAXS/WAXS, thermal treatments. Not all these options have been explored so far. Whereas for CNT fibres and sheets there is a significant amount of mechanical data in the literature, testing of individual CNT bundles (i.e., building blocks of the nanoscale network) yet remains a challenge because of their length, intrinsic entanglement at the aerogel-state, the lack and/or technical complexity of testing methods. Besides, FCCVD produces inherently polydisperse 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. Transversal TEM analysis of FIB-milled macroscopic fibres demonstrates the importance of CNT bundling and packing efficiency.
The work will highlight the development of nanomechanical tests of individualized CNT bundles coupled with in situ TEM and/or Raman spectroscopy and its potential applicability in the analysis of advanced materials (bundles, fibres, sheets). The feasibility of complex experimental evaluation of their structure and performance will be discussed along with the types of defects that may be generated under the beam-exposure. Such evaluation could serve as a guideline for the choice of the high-performance material in the future.