Polycarbonate/Carbon Nanotubes Nanocomposites as Liquid Sensors

Polycarbonate (PC)/multi walled carbon nanotubes (MWCNTs) nanocomposites with different compositions were produced via melt mixing. The main objective of this study was using of changes in the electrical properties of nanocomposites in contact with various solvents, to produce a material for solvent sensing. TEM micrographs confirmed uniform distribution of the tubes within the polymer matrix and the formation of a conductive network. Electrical conductivity measurements showed a percolation threshold bellow 1 wt.% CNTs for this system. To investigate their sensing performance, the samples were immersed in four different solvents having solubility parameters close to that of PC. All solvents could reduce the electrical conductivity of the nanocomposites, however the magnitudes and time dependent characteristics of the conductivity change were distinct and different for each solvent. Therefore, these nanocomposite samples could be potentially used as solvent sensors. The effect of nanotube content and the type of solvent on the sensory behavior of the samples were studied.