Lightweight leaf-structured carbon nanotubes/graphene foam and the composites with polydimethylsiloxane for electromagnetic interference shielding

One of the key requirements for novel electromagnetic interference (EMI) shielding composites is lightweight. In this article, we report a kind of novel foam materials (labeled as CGF) with a leaf structure composed of carbon nanotubes (CNTs) and reduced graphene oxide (rGO) for EMI shielding. It was found that adding 20 wt% CNTs into the new material could expand the conductive network and increase the conductivity of CGF by 274.4%. Such an expansion could facilitate the multiple reflections and absorptions of EMWs within the materials and boost the conversion efficiency to induced currents (ICs), resulting in excellent total EMI shielding effectiveness (SE) of 71.4 dB at mass per unit area of only 12.5 mg·cm−2. Moreover, the CGF materials manifest exceptional EMI SE divided by density (SED) or mass per unit area (SEMA) value were 1142 dB·cm3·g−1 and 5712 dB·cm2·g−1, respectively. Considering the radar chart prepared by the total EMI SE, SED and SEMA, CGF reflects excellent comprehensive performance. Being compounded with polydimethylsiloxane (PDMS), the EMI SE of CGF/PDMS show excellent pressure resistance. After press CGF/PDMS for 100 times under a pressure of 500 kPa, the EMI SE retention rate can reach 71.6%. Furthermore, the addition of CGF increase the heat resistance indexes (THRI) of the composites by 6 °C. In conclusion, CGF/PDMS are extremely practical in the field of EMI shielding. [Display omitted] •Design and fabricate a leaf-structured CNTs/rGO foam (CGF) for EMI shielding.•CNTs were seamlessly embedded into the hole wall of rGO by the π-π interaction.•Take into account SEtot, mass per unit area and density, CGF has high comprehensive performance.•EMI SE retention rate of CGF/PDMS is up to 71.6 % after press it for 100 times.