Magnetic segregation effect in liquid crystals doped with carbon nanotubes.

We study the orientational transitions in a suspension of carbon nanotubes in a nematic liquid crystal induced by an external magnetic field. The case of a finite orientational anchoring of liquid crystal molecules at the surface of doped carbon nanotubes is considered. It is shown that in a magnetic field the initial homogeneous planar texture of the liquid crystal-carbon nanotubes mixture is disturbed in a threshold manner (Fréedericksz transition).

Magnetic field induced orientational transitions in liquid crystals doped with carbon nanotubes.

We propose a continuum theory of orientational phase transitions induced by an external magnetic field in a suspension of carbon nanotubes in a nematic liquid crystal. It is shown that in a magnetic field a non-uniform and two different uniform phases are possible in the suspension. The uniform phases of the suspension differ by the type of orientational coupling of nanotubes with the liquid crystal matrix (the planar type when the nanotubes are oriented along the matrix director, and the homeotropic type when the nanotubes are perpendicular to the director).