Details

Autor(en) / Beteiligte

• Schymura, Stefan
• Dölle, Sarah
• Yamamoto, Jun
• Lagerwall, Jan

Titel

Filament formation in carbon nanotube-doped lyotropic liquid crystalsElectronic supplementary information (ESI) available: Movie of filament drawing from a CNT-loaded LC. See DOI: 10.1039/c0sm01225d

Erscheinungsjahr

2011-03

Quelle

Alma/SFX Local Collection

Beschreibungen/Notizen

• By introducing carbon nanotubes (CNTs) into lyotropic nematic liquid crystals, strongly enhanced viscoelastic behaviour results, allowing the extraction of very thin and long filaments in which the CNTs are uniformly aligned. The filament formation requires the liquid crystallinity of the host phase and it does not take place for coarsely dispersed nanotubes or if their concentration is below a threshold value. The type of nanotube plays only a small role, single- as well as multiwall CNTs both trigger the filament formation, but spherical C 60 fullerenes do not give rise to the phenomenon. We argue that individualized CNTs stiffen the rod-shaped micelles of the liquid crystal host and that the elongational flow then increases the nematic long-range order as well as the micelle length. If the CNTs are present at a sufficient concentration to connect in continuous linear chains of arbitrary extension, the micelle stiffening is ensured regardless of length, taking the system into a positive feedback loop between increasing orientational order and diverging micelle length. It is this percolation-like transition to aligned and quasi-infinite micelles stabilized by chains of nanotubes that makes the filament formation possible. Carbon nanotubes are introduced into lyotropic nematic liquid crystals, resulting in the extraction of very thin and long filaments in which the CNTs are uniformly aligned.