Fabrication of binary to quaternary PVDF based flexible composite films and ultrathin sandwich structured quaternary PVDF/CB/g-C3N4/BaFe11.5Al0.5O19 composite films for efficient EMI shielding performance

This work reports the facile fabrication of binary, ternary, and quaternary polymer composite films using combinations of Polyvinylidene fluoride (PVDF), Carbon Black (CB), Graphitic carbon nitride (g-C3N4), and Aluminum doped Barium hexaferrite (BaFe11.5Al0.5O19) nanoplatelets for application as EMI shielding materials at X-band frequency. The excellent total EMI-SE of 47.39 dB in X-band for ultra-small thickness of 0.193 mm was observed for the quaternary PVDF/CB/g-C3N4/BaFe11.5Al0.5O19 composite film. The quaternary composite film was further hot pressed into sandwich-structured two-layer and three-layer composite films. The sandwich and/or multi-layered structure of the PVDF/CB/g-C3N4/BaFe11.5Al0.5O19 composite film improved the EMI shielding performance through multiple reflection loss. With the addition of intact conduction of fillers and multiple-reflection-absorption effect, the multi-layered composite structure attained the best shielding efficiency (SE) of 64.54 dB.