  Microstructure, phase transitions, electrical conductivity, and optical and
electrooptical properties of multiwalled carbon nanotubes (NTs), dispersed in
the cholesteric liquid crystal (cholesteryl oleyl carbonate, COC), nematic 5CB
and their mixtures, were studied in the temperature range between 255 K and 363
K. The relative concentration X=COC/(COC+5CB)was varied within 0.0-1.0. The
concentration $C_p$ of NTs was varied within 0.01-5% wt. The value of X
affected agglomeration and stability of NTs inside COC+5CB. High-quality
dispersion, exfoliation, and stabilization of the NTs were observed in COC
solvent ("good" solvent). From the other side, the aggregation of NTs was very
pronounced in nematic 5CB solvent ("bad" solvent). The dispersing quality of
solvent influenced the percolation concentration $C_p$, corresponding to
transition between the low conductive and high conductive states: e.g.,
percolation was observed at $C_p=1%$ and $C_p=0.1%$ for pure COC and 5CB,
respectively. The effects of thermal pre-history on the heating-cooling
hysteretic behavior of electrical conductivity were studied. The mechanism of
dispersion of NTs in COC+5CB mixtures is discussed. Utilization of the mixtures
of "good" and "bad" solvents allowed fine regulation of the dispersion,
stability and electrical conductivity of LC+NTs composites. The mixtures of COC
and 5CB were found to be promising for application as functional media with
controllable useful chiral and electrophysical properties.
