Real nanocomposites effect in carbon nanotubes / polymers

Dispersion and percolation of MultiWall Carbon NanoTubes (MWCNT) was studied in silicon oils by means of electrical measurements. After MWCNTs were homogenously dispersed with ultrasounds in silicon oil, the composite was slowly diluted to obtain a large number of filler content. Conductivity measurements were done for each filler content allowed us to determine the percolation threshold and the corresponding critical exponent with an unmatched accuracy. A decrease of percolation threshold over time has been observed over time and was correlated to MWCNT aggregation. More surprising, critical exponent also varies over time, which suggests a strong correlation with the quality of the filler dispersion in the matrix. Owing to the large number of data collected, a model derived from static percolation was established. The latter describes conductivity as a function of time and filler content.