SAW study of structural changes in liquid crystals doped with carbon nanotubes induced by electric and magnetic fields

Abstract

The doping of liquid crystals (LCs) with carbon nanotubes and magnetic nanoparticles have attracted wide interest in many areas of science, technology and medicine. LCs occur as additional, thermodynamically stable states of matter between the liquid state and the crystal state in some materials. They can be characterized by a long-range orientational order of the molecules and, as a consequence, by an anisotropy in their physical properties. LCs can be oriented under electric or magnetic fields due to the anisotropy of dielectric permittivity or diamagnetic susceptibility. Carbon nanotubes are molecular scaled tubes of graphitic carbon with outstanding properties. The simplest nanotube is composed of a single sheet of a network of carbon atoms, called graphene, which is rolled up into a tubular form. Because of the small value of the anisotropy of the diamagnetic susceptibility of liquid crystals, the idea of doping them with fine magnetic particles was also introduced. Nanotubes can undergo functionalization, including by magnetic particles, to produce novel hybrid materials potentially suitable for applications.