Electrical, optical, and mechanical percolations of multi-walled carbon nanotube and carbon mesoporous-doped polystyrene composites:

In this study, we have investigated and compared electrical, optical, and mechanical properties of polystyrene thin films with added multi-walled carbon nanotube and carbon mesoporous. Surface conductivity (sigma), scattered light intensity (I-sc), and all the mechanical parameters of these composites have increased with increasing the content of carbon filler (multi-walled carbon nanotube or carbon mesoporous) in the polystyrene composites. This behavior in electrical, mechanical, and optical properties of the polystyrene/carbon fiber composites has been explained by classical and site percolation theory, respectively. The electrical percolation thresholds (R-sigma) were determined to be 8.0 wt% for polystyrene/multi-walled carbon nanotube and 25.0 wt% for polystyrene/carbon mesoporous composites. The optical percolation thresholds were found to be R-op = 0.8 wt.% for polystyrene/multi-walled carbon nanotube and R-op = 3.0 wt.% for polystyrene/carbon mesoporous composites. For the polystyrene/carbon mesoporous composite system, it was determined that the mechanical percolation threshold occurred at lower R values than the polystyrene/multi-walled carbon nanotube composite system. The electrical (beta(sigma)), optical (beta(op)), and mechanical (beta(m)) critical exponents have been calculated for both of the polystyrene/carbon fiber composites and obtained as compatible with used percolation theory.