Structural transitions in nematic liquid crystals doped with magnetite functionalized single walled carbon nanotubes

The 4-(trans-4′-n-hexylcyclohexyl)-isothiocyanatobenzene (6CHBT) nematic liquid crystal was doped with single walled carbon nanotubes (SWNTs) and with magnetite labeled single walled carbon nanotubes (SWNTs/Fe3O4). Prepared samples were characterized by infrared spectroscopy, transmission electron microscopy, optical microscopy and by magnetic measurements. Electric and magnetic Freedericksz transitions were measured for the pure liquid crystal, and for the liquid crystal doped with SWNTs, as well as with SWNTs/Fe3O4 (volume concentration ϕ=10−4). The density of anchoring energy at the nematic—magnetic particle boundary was determined. The value of the anchoring energy density for SWNTs/Fe3O4 is lower than for SWNTs. The critical voltage of the Freedericksz transition depends significantly on the bias magnetic field.