Ultralight\nGraphene Foam/Conductive Polymer Composites for Exceptional Electromagnetic\nInterference Shielding

Abstract

Ultralight,\nhigh-performance electromagnetic interference (EMI) shielding graphene\nfoam (GF)/poly­(3,4-ethylenedioxythiophene):poly­(styrenesulfonate)\n(PEDOT:PSS) composites are developed by drop coating of PEDOT:PSS\non cellular-structured, freestanding GFs. To enhance the wettability\nand the interfacial bonds with PEDOT:PSS, GFs are functionalized with\n4-dodecylbenzenesulfonic acid. The GF/PEDOT:PSS composites possess\nan ultralow density of 18.2 × 10^–3 g/cm³ and a high porosity of 98.8%, as well as an enhanced electrical\nconductivity by almost 4 folds from 11.8 to 43.2 S/cm after the incorporation\nof the conductive PEDOT:PSS. Benefiting from the excellent electrical\nconductivity, ultralight porous structure, and effective charge delocalization,\nthe composites deliver remarkable EMI shielding performance with a\nshielding effectiveness (SE) of 91.9 dB and a specific SE (SSE) of\n3124 dB·cm³/g, both of which are the highest among\nthose reported in the literature for carbon-based polymer composites.\nThe excellent electrical conductivities of composites arising from\nboth the GFs with three-dimensionally interconnected conductive networks\nand the conductive polymer coating, as well as the left-handed composites\nwith absolute permittivity and/or permeability larger than one give\nrise to significant microwave attenuation by absorption.