Enhanced Interfacial Interactions of a Flexible Electromagnetic Interference Shielding Nanocomposite Using a T-Shaped Conjugated Surfactant

In this study, we develop a highly flexible and lightweight electromagnetic interference shielding (EMIS) nanocomposite film based on electrochemically exfoliated graphenes (EEGs), employing a brick-and-mortar structure. A T-shaped conjugated surfactant is synthesized to effectively exfoliate and disperse the aggregated EEGs in the solvent and matrix. The resulting nanocomposite film exhibits well-aligned and tightly bound conductive multilayered nanostructures due to the synergetic interactions of its brick-and-mortar components. The EMIS film, with a thickness of approximately 100 μm, exhibits outstanding mechanical properties, including a tensile strength of 20.7 MPa and Young’s modulus of 1.15 GPa. Notably, it demonstrates exceptional folding reliability by withstanding over 100000 folding/unfolding cycles, which surpasses the performance of previously reported foldable EMIS films. In addition, the well-ordered conductive multilayers composed of the EEGs contribute to the excellent EMIS performance that exceeds 30 dB in the X-band frequency range, effectively blocking more than 99.9% of electromagnetic waves within this range. These results are ascribed to the well-developed supramolecular brick-and-mortar nanostructure, which originates from the synergistic effects of complex interfacial interactions, including π-π, ionic, and hydrogen-bonding interactions. This study also proposes a mechanism that explains the remarkable mechanical properties and significantly enhanced folding reliability of the developed EMIS film.