Recently two-dimensional transition metal carbides and nitrides (MXenes) have attracted tremendous attention due to their appealing properties such as exceptional electrical conductivity and electromagnetic interference (EMI) shielding. These notable properties have motivated the fabrication of MXene-based films. However, pristine MXene films have low mechanical stability, and current technologies for developing MXene-based films are tedious, expensive, and unable to produce large films. Herein, we report a novel fabrication method that improves the film-forming ability of Ti3C2Tx MXene and enhances the mechanical properties of the final films, enabling the fabrication of large, ultrathin, uniform, and flexible MXene-based films. The method involves the incorporation of Ti3C2Tx nanosheets into poly(3,4-ethylene dioxythiophene) polystyrene sulfonate (PEDOT:PSS) and the fabrication of Ti3C2Tx /PEDOT:PSS films by drop-casting. The Ti3C2Tx/PEDOT:PSS composite did not show the coffee ring or concentrated stain effect, which is the common bottleneck in drop-casting and inject printing technologies. It has superior electrical conductivity and EMI shielding, and is flexible. The uniformity of the drop-casted Ti3C2Tx/PEDOT:PSS is attributed to the gel transition of colloids during the solvent evaporation and the ability of PEDOT:PSS polymer chains to anchor themselves firmly to the surface-activated polycarbonate sheet. Using a co-treatment technique, the electrical conductivity and EMI shielding properties of the Ti3C2Tx/ PEDOT:PSS composite was improved to the order of those properties of pure Ti3C2Tx films. The resulting nanocomposite films demonstrated excellent mechanical properties as they withstood 500 bending cycles. The superior electrical conductivity and EMI shielding, as well as the flexibility, attractive mechanical properties, and ease of fabrication of large films of the composite point to the great potential of the composite for next generation EMI shielding.

Ultrathin Ti3C2Tx/PEDOT:PSS films for electromagnetic interference shielding

ACS Spring Meeting 2021

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