Reduced graphene oxide layers full of bubbles for electromagnetic interference shielding

Carbon materials with a three-dimensional (3D) conductive network have attracted considerable research and commercial interest due to their low density and high electrical conductivity toward electromagnetic interference (EMI) shielding. In the present work, an ensemble of reduced graphene oxide (rGO) layers full of bubbles made by the template-free method employed vitamin C (VC) as a reduction agent at low temperatures. The effect of the VC amount on the EMI shielding effect (SE), electrical conductivity, and compressive strength of rGO bubbles was investigated. The results showed that the EMI SE and electrical conductivity all increased with the increase in VC until the ratio reached 1. rGO bubbles prepared with a VC/GO ratio of 1 had a low density of 0.06 g cm(-3), high porosity of 94%, but high compressive strength of 0.0033 MPa at a strain of 4%. Bubbles with a thickness of 1.346 mm exhibited a respectable EMI shielding effectiveness (SE) of 70 dB and SE/density (SET/rho) of 1167 dB cm(3) g(-1) at the X-band and higher than 54 dB in the wideband region of 2-18 GHz. The excellent EMI SE was mainly ascribed to the conductive dissipation, and the multiple reflections and the repeated scattering of the bubble structure. This work provides some insight into preparing an ensemble of reduced graphene oxide layers with bubbles, which has potential applications in the EMI shielding field.