In situ construction of efficient electromagnetic function Graphene/PES composites based on liquid phase exfoliation strategy

Although graphene nanosheets (GNs) with huge specific surface area and exceptional electrical properties exhibit attractive practical prospect in the realm of electromagnetic function materials, how to optimize the distribution states of GNs in matrix is still a challenge. In this work, the suspension of GNs was prepared directly via an efficient liquid-phase exfoliation (LPE) process in N-octyl-2-pyrrolidone (NOP). Thanks to the dissolution of polyether sulfone (PES) in NMP and NOP solvent, the GNs/PES composites were in-situ prepared via a facile solution blending in combination with evaporation process. The "function units" of the mesoscopic micro-cluster structure assembled by GNs during the solvent evaporation process contribute to optimized impedance matching characteristics and loss capabilities as well as excellent electromagnetic wave (EMW) absorbing performance of the as-constructed GNs/PES electromagnetic composites. Particularly, the as-prepared sample G-P-9 with a graphene content of as low as 9.0 wt% exhibits outstanding EMW absorbing performance in the whole ranges of tested frequency (8.2–12.4 GHz) and temperature (293–453 K) with a minimum reflection loss (RL) of −52.7 dB. Besides, the in-situ self-assemble GNs/single-walled carbon nanotubes (GNs/SWCNT) film with pre-constructed three-dimensional interpenetrating conductive network exhibits excellent electromagnetic interference (EMI) shielding effectiveness (SE) of about 5.1 × 104 dB cm2 g−1. The present approach would be applicable to construct high-performance electromagnetic functional materials and broaden the application prospect of high-integrity graphene nanosheets.