Highly conductive polystyrene/carbon nanotube/PEDOT:PSS nanocomposite with segregated structure for electromagnetic interference shielding

Highly conductive polymer nanocomposites (CPNs) are promising alternatives to metals for electromagnetic interference (EMI) shielding applications. However, constructing a well-established conductive network within a polymer matrix using conventional processes is still challenging. This research aimed to improve the EMI shielding performance of CPNs by developing highly conductive segregated structures through a facile innovative dispersion mixing process. The nanocomposites were fabricated by dispersing polystyrene beads (PS), CNT, and PEDOT:PSS in deionized water, followed by vacuum filtration, solvent treatment, and hot press molding. The employed technique effectively constructed a highly conductive network in the PS/CNT nanocomposite, resulting in the lowest ever reported percolation threshold of 0.009 vol% among CNT-based segregated structures. Moreover, adding PEDOT:PSS to the nanocomposite as an additional constituent significantly promoted the conductive network by improving the dispersion of CNTs and the interparticle contact. The PS/CNT/PEDOT:PSS (100:2:4 w/w/w) exhibited a high electrical conductivity of 2.352 S/cm with notable specific EMI shielding effectiveness (SE) of 55.7 dB/mm (with dominant absorption mechanism), which is among the best performance reported for CNT-based conductive segregated structures, to the best of our knowledge. In brief, this work proposed a novel approach of using a facile, cost-effective, and eco-friendly method to fabricate highly CPNs for EMI shielding applications.