A strategy to achieve high electromagnetic interference shielding and ultra low percolation in multiwall carbon nanotube-polycarbonate composites through selective localization of carbon nanotubes

Here, we report a simple method that involves solution blending of polycarbonate (PC) in the presence of multiwall carbon nanotubes (MWCNTs) and commercial PC beads for the preparation of electrically conducting MWCNT-PC composites with high electromagnetic interference shielding effectiveness (EMI SE) and electrical conductivity at very low (similar to 0.021 wt%) percolation threshold (p(c)). Thus, electrical conductivity of similar to 4.57 x 10(-3) S cm(-1) was achieved in the MWCNT-PC composites at an extremely low MWCNT loading (0.10 wt%) in the presence of 70 wt% PC beads in the composites. Finally, optimizing the ratio of PC beads and MWCNT loading in the composites, a very high EMI SE value (similar to 23.1 dB) was achieved at low loading (2 wt%) of MWCNT with 70 wt% PC beads. The effective concentration of MWCNT increases in the solution blended PC region with increasing the amount of PC beads. Thus, a strong interconnected conductive network structure of CNT-CNT is developed throughout the matrix and the presence of strong pi-pi interaction among the electron-rich phenyl rings of PC and MWCNT in the composites plays a crucial role in increasing the EMI shielding value and electrical conductivity of the MWCNT-PC composites.