Dispersion of Carbon Nanotubes in Polymer Matrices using Trifluoroacetic Acid as a Co-solvent

We report a simple approach of dispersing multi-walled carbon nanotubes (MWNTs) in a polymer matrix using trifluoroacetic acid (TFA) as a co-solvent. TFA is a low boiling point organic acid that is highly miscible with many organic solvents. MWNTs were readily dispersed in organic solvents mixed with 5-10 v{\%} of TFA after mild sonication. The dispersed MWNT solution was then mixed with polymer solution to obtain a uniformly dispersed nanoparticle/polymer mixture solution. From this solution, nanocomposite films were prepared using drawdown bar method. The dispersion of MWNTs in solution and in dried polymer matrix on a glass substrate was studied by dynamic light scattering and scanning electron microscopy. The electrical conductivity of the carbon nanotube/polymer composite films with different loading ratio of MWNTs dispersed on a glass substrate was measured using two probe technique. A percolation threshold of 0.67 wt{\%} MWNTs was found from the nanocomposite films. At a loading ratio of 1.25 wt{\%} of MWNTs, the conductivity of the composite material was increased to the order of 10$^{-3}$ S/cm.