Construction of a Layered-Cavity Structure via Spin-Coating a PEDOT:PSS/PEO/SWCNT Suspension onto PBAT/MWCNT Electrospun Films and the Enhanced Electromagnetic Shielding Performance

The development of porous films with biodegradability, high electromagnetic interference (EMI) shielding, and thermal conducting performance for advanced electronics is urgent. Herein, a superthin and flexible film composed of PBAT/MWCNT and PEDOT:PSS/PEO/SWCNT is fabricated through combining electrospinning and spin-coating. In this work, the content of PEO and SWCNT should be controlled to 1 and 10 wt % for achieving the optimal layered-cavity structure within the film, guaranteeing the proper flow ability of the suspension. The robustly constructed layered-cavity structure within the film allows the electromagnetic waves to suffer multiple reflections, which enhances the EMI shielding performance. Meanwhile, the structure also plays an important role in promoting the electric and heat conduction of the film. Consequently, the film with a thickness of 0.14 mm exhibits the most optimal EMI shielding efficiency (SE) of 26.02 dB, electrical conductivity of 40.371 S/m, and thermal diffusion coefficient of 0.124 mm2/s. The EMI SE/thickness is about 185.86 dB/mm, attaining a cutting-edge level compared to reported polymer-based films. Besides, the PEO or SWCNT content should be controlled, and the two-side spin-coating is also needed for thicker films. This work offers a method to develop superthin biodegradable films with excellent performance, positioning it as a strong alternative for flexible electronics.