Liquid Crystals of DNA‐Stabilized Carbon Nanotubes

Carbon Nanotubes in Liquid Crystals

“…With MWCNTs some ten times higher loading should be required. While experimental observations with 20 MWCNTs 34,35,38 come close to the theoretical predictions, liquid crystallinity from SWCNTs have generally required higher loading than anticipated based on the Onsager theory 36,37 , only one work 32 coming close to the predicted 0.5 wt.-%.…”

“…We end this review with a discussion of the case that the LC is not a host for the CNTs, but rather it is formed by the CNTs themselves, a research field that has been developed mainly by the groups around Windle 34,35,38 , Poulin 32,36,49 and Smalley 33,37,59 . The basis for this phenomenon is the classical Onsager argument for liquid crystal phase formation in concentrated suspensions of rigid rods 60,61 : if the aspect ratio of the rods and their concentration are both large enough, the free energy of the system is reduced by forming a nematic 10 phase, the cost of reduced orientational entropy being less than the gain in translational entropy (the latter corresponds to a decrease of excluded volume).…”

Carbon Nanotubes Engineering Assisted by Natural Biopolymers

“…However, those solutions are not suitable for composite material preparation, which the mild solution processing is required. For biopolymer could disperse CNT at high concentration, the anisotropic birefringence phenomenon of liquid crystal phase was earlier found in 2005 for DNA stablized CNTs (Badaire, et al 2005). Later the spontaneous nematic phase separation of CNTs stabilized in aqueous biological hyaluronic acid solutions was also observed ).The initially obtained SWNT dispersion is isotropic single-phase.…”

Macroscopic-scale carbon nanotube alignment via self-assembly in lyotropic liquid crystals

“…Here we discuss the approach of dispersing the nanotubes in a liquid crystalline matrix [6,10,12,13], a fluid exhibiting long-range orientational order, in some cases together with positional order. In fact, under the right conditions, CNTs can form liquid crystal phases on their own [14][15][16][17], just like any sufficiently concentrated suspension of sufficiently anisometric particles, as predicted by Onsager [18]. It is however highly challenging to reach acceptable CNT dispersion at the concentration required, and even if this threshold is reached, there is up until today no method known to obtain a large-scale uniform alignment of the sample.…”