Stabilization of liquid crystal blue phases by carbon nanoparticles of varying dimensionality.

Abstract

The thermal stabilization of blue phases is a subject that has been of scientific and technological interest since their discovery. Meanwhile, carbonaceous nanomaterials such as C60 fullerenes, carbon nanotubes and graphene have generated interdisciplinary interest spanning across solid-state physics, organic chemistry, colloids, all the way to soft matter physics. Herein, the stabilization of liquid crystal blue phases by doping with C60, single-walled carbon nanotubes and graphene oxide is described. All three types of particles are found to extend the combined temperature range of blue phases I and II by a factor of ∼5. Furthermore, mixtures of pairs of different materials, and all three types are shown to stabilize the blue phases. The temperature range of the blue phases is shown to grow at the expense of the cholesteric phase. This leads to a blue phase-cholesteric-smecticA phase triple-point in all cases except that of doping with carbon nanotubes. The mechanisms of this thermal stabilization are discussed in light of theoretical descriptions for other established systems.