Enhancing the electromagnetic interference shielding of flexible films with reduced graphene oxide-based coatings

Herein, it was investigated the development of a low-cost conductive coating for application in the field of Electromagnetic Interference shielding (EMI shielding). The coating was produced with reduced graphene oxide (rGO), considered an excellent technological alternative for graphene applications, and styrene-ethylene/ butylene-styrene (SEBS) block copolymer. The rGO was obtained by reduction of graphene oxide (GO) using ascorbic acid as a "green" and efficient reducing agent, and Raman spectroscopy results indicated that the reduction of GO was successfully reached. Firstly, polymeric substrates were covered with coatings containing 2% (v/v) of rGO to evaluate the electrical conductivity and electromagnetic shielding effectiveness of transmission (SET). With the best SET value achieved, the block copolymer SEBS was added to the rGO coating to improve its adhesion over the substrate. Electrical conductivity and SET of these samples were measured by Impedance Spectroscopy and EMI Shielding analysis, with the later performed within the 10 GHz frequency band (X band), required for radar, telecommunication and military applications. With attenuation of the electromagnetic waves around 20 dB, this new route/technique can be used to improve the shielding effectiveness of flexible films by rGO coating, for wide range technological sectors.