Composites of single-walled carbon nanotubes and polystyrene: Preparation and electrical conductivity

Composites of single-walled carbon nanotubes (SWNT) and polystyrene have been prepared using three different types of SWNT: HiPco, CoMoCat, and pulsed laser vaporization (PLV). Nanotubes were incorporated into the polystyrene matrix by two methods: (1) evaporation of chloroform solutions of SWNT noncovalently functionalized with poly [(m-phenylenevinylene)-co-(2,5 -dioctoxy-p-phenylenevinylene)] (PmPV) and polystyrene; (2) coagulation in water of DMF solutions containing polystyrene and nitric acid oxidized SWNT. From measurements of the electrical conductivities of the composites over a range of concentration from 0.1 to 6 wt % SWNT, the percolation threshold of conductivity was 0.17 - 0.3% SWNT for the PmPV-coated materials and 0.4 - 0.5% for those made by coagulation. Of the three types of SWNT, composites made with HiPco tubes had the highest conductivity.