Cotton Fabric Coated with Silver/Carbon Nanotubes and Iron Oxide/Chitosan-Modified Polyurethane for Enhanced Electromagnetic Shielding

Electromagnetic interference (EMI) shielding materials based on conventional polymer composites raised environmental concerns due to their nondegradability. Therefore, the development of environmentally friendly materials for EMI shielding applications is in great demand. In this work, biomass cotton fabric served as the skeleton, and silver nanoparticles (Ag)/carbon nanotubes (CNTs) conductive networks and a chitosan-blocked biodegradable polyurethane (CPU)/Fe3O4 layer were formed on the surface of the cotton fabric through silver-plating and dip-coating methods. The Fe3O4/CPU surface layer enhanced the impedance matching at the sample–air interface and EM absorption ability through interior magnetic loss, while the synergistic Ag/CNTs conductive networks in the middle layer contributed to the multiple reflections and scattering of EM waves. As a result, the Fe3O4/CPU/Ag/CNTs coated cotton fabric achieved an impressive EMI shielding effectiveness of >73.77 dB over the X-band frequency range with an absorption coefficient of 0.24. Furthermore, the composite fabric also exhibited highly reliable EMI shielding ability during the bending, washing, and acid/alkali treatment tests. Consequently, the fabricated fabric will benefit the development of ecofriendly and sustainable EMI shielding materials.