Aligned, carbon nanofibers containing barium titanate and their polydimethylsiloxane composites for electromagnetic interference shielding

The rapid development of wireless communication technology and miniaturization of electronic devices have escalated the demand for high-performance electromagnetic interference (EMI) shielding materials which are light weight, waterproof, and flexible. Herein, we have demonstrated fabrication of aligned and non-aligned one-dimensional (1-D) N-doped carbon nanofibers (CNF) incorporated with barium titanate (BaTiO3) nanoparticles (NPs) [BaTiO3–CNF] for EMI shielding in X, Ku, and K-band. BaTiO3–CNF was prepared through electrospinning followed by carbonization at 900 °C. The aligned BaTiO3–CNF exhibited better EMI shielding effectiveness (81 dB with a thickness of 0.24 mm) compared to the non-aligned BaTiO3–CNF (59.2 dB). Alignment of N-doped CNF enhanced electronic conduction in axial direction of the fibers and exhibited higher electrical conductivity of 1.4 S cm−1. The alignment also improved multiple internal reflections and interfacial polarization in the layered structure of the CNF. PDMS composites of BaTiO3–CNF were prepared by hand-layup method to make them flexible, and the composites exhibited similar EMI shielding properties as that of BaTiO3–CNF. Alignment of suitably doped CNF may open up new opportunities for industrial-scale production of shielding materials that are waterproof, lightweight, and flexible.