Facile fabrication of highly conductive and robust three-dimensional graphene/silver nanowires bicontinuous skeletons for electromagnetic interference shielding silicone rubber nanocomposites

Backfilling polymer matrix into the preformed three-dimensional (3D) conductive filler skeleton is a burgeoning strategy for developing highly conductive polymer composites (CPCs). For this strategy, the success construction of highly conductive and robust skeletons is the prerequisite. In this study, choosing the complementary graphene oxides (GOs, good water dispersibility ∼15 mg/mL) and silver nanowires (AgNWs, excellent conductivity ∼106 S/cm) as building blocks, highly conductive (12.1 S/cm) and robust 3D reduced GOs (rGOs)/AgNWs bicontinuous conductive skeletons (GACSs) were successfully constructed by freezing partially reduced GOs/AgNWs hydrogel technique that can increase the pore sizes, pore-wall thickness and homogeneity of GACSs. The resultant polydimethylsiloxane (PDMS)/rGOs/AgNWs composite (PGAC) with a low filler loading of 0.76 wt% possesses superior conductivity of 10.6 S/cm, absorption-dominated electromagnetic interference shielding efficiency (EMI SE, 34.1 dB) and high-level specific SE (SSE, total SE divided by filler loading and thickness) up to 22.43 dB/unit wt%/mm (most common values of 0.66–12.5 dB/unit wt %/mm). Simultaneously, PGACs exhibit excellent compression property, thermal stability and flame retardancy.