Electrical conductivity of polystyrene/poly(n-alkyl methacrylate)s / carbon nanotube ternary composite casting films

In this work, poly(n-alkyl methacrylate)s (P-alkyl-MA)/Polystyrene (PS)/Carbon nanotube (CNT) composite films with different CNT concentration and polymer blend ratio were prepared utilizing solution casting method. Light microscope and scanning electron microscope were used to investigate the CNT location in polymer blends and morphology of ternary composite films. The electrical conductivity of the films were investigated, all the percolation thresholds (ϕc) of PS/P-alkyl-MA/CNT composite films were determined and the experimental data are fitted utilizing McLachlan’s equation. The fitting data indicate both PS/PMMA/CNT and PS/PEMA/CNT composite films show an obviously double percolation effect with polymer blend ratio at 50/50. Compared with pure PMMA and PEMA, the ϕc of composite films when polymer blend ratio at PS /PMMA =50/50 and PS/PEMA =50/50 were decreased by 69.0% and 73.1%, respectively. A contour plot based on all PS/PMMA/CNT and PS/PEMA/CNT experimental data were presented to show the electrical conductivity as a function of CNT concentration and polymer blend ratio. With PS content increasing in P-alkyl-MA/PS blends, the conductivity of both PS/PMMA/ CNT and PS/PEMA/ CNT composite films shows a similar tendency. The morphology with different polymer blend ratio at a certain CNT concentration and different CNT concentration at a certain polymer blend ratio was presented to explain the conductivity and ϕc of ternary composite films changing tendency.