  The microstructure and electrical conductivity of suspensions of multi-walled
carbon nanotubes (MWCNTs) in binary liquid mixtures
water-1-Cyclohexyl-2-pyrrolidone (CHP) were studied in the heating and cooling
cycles. The concentration of MWCNTs was varied in the interval between 0-1 wt.%
and the content of water in a binary mixture X = [water]/([CHP]+[water]) was
varied within 0-1.0. The experimental data have shown that dispersing quality
of MWCNTs in a mixture of good (CHP) and bad (water) solvents may be finely
regulated by adjustment of composition of the CHP+ water mixtures. The
aggregation ability of MWCNTs in dependence on X was discussed. The surface of
MWCNT clusters was highly tortuous, its fractal dimension df increased with
increase of X, approaching -> 1.9 at X->1. It was concluded that the surface
tension is not suitable characteristic for prediction of dispersion ability in
the mixture of good and bad solvents. The electrical conductivity data
evidenced the presence of a fuzzy-type percolation with multiple thresholds in
the systems under investigation. This behavior was explained by formation of
different percolation networks in dependence of MWCNT concentration.
