Carbon nanotubes are most promising candidates for the development of advanced functional materials because of their nanometric dimensions combined with remarkable electrical, mechanical and thermal properties. Almost all carbon nanotube composites studied so far have however failed to display the desired behaviour because of insufficient order in the systems. Finding a simple, efficient and reproducible way to control the alignment of the nanotubes thus appears a key step in the further development towards carbon-nanotube-based devices.
The aim of this interdisciplinary project is to solve the alignment problem by utilizing the self-organizing properties of liquid crystals. The possibility to transfer the order of a liquid-crystalline host onto the nanotubes has recently been demonstrated, but an understanding of which mechanisms are involved is lacking. With a profound understanding of the processes involved in the liquid-crystal-assisted nanotube dispersion and alignment, an optimisation of the host is possible which may dramatically improve the properties of the composite.
A systematic study involving a series of related liquid crystalline substances, exhibiting strategically chosen differences in their molecular structures, will be performed to understand how the molecules adsorb on the nanotube surface. The different composites will be characterized with various techniques, primarily polarized Raman spectroscopy which has been proven efficient in assessing the state of nanotubes embedded in an organic host.
The degree of macroscopic order can be measured quantitatively and by monitoring the vibrational modes of the nanotubes the molecular interactions involved in the adsorption process can be studied. As the liquid crystal provides not only static alignment but also a means of reorienting the nanotubes by applying an electric field, we will also employ time-resolved Raman spectroscopy for following the dynamics of the reorientation mechanisms.
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