Fabrication of effective electromagnetic shielding leather with a chromium-free multi-network structure

Chrome-free tanning and intelligentization are hot topics in leather-related research. In this work, green chrome-free tanned electromagnetic shielding leather is proposed based on the modification of skin collagen fibers using polyionic liquids (PILs), metal-organic framework-layered double hydroxide (MOF-LDH), and polyaniline (PANI). First, a network-interspersed PILs/MOF-LDH-Zr structure was synthesized using MOF-LDH, ionic liquid, methacrylic acid, and zirconium sulfate as raw materials based on a radical polymerization approach. Then, PANI was grown in situ on the surface of the leather to help construct a green chrome-free tanned electromagnetic shielding leather with a leather shrinkage temperature of 94.5 °C and an effective EMI shielding capability of 32.3 dB. The enhanced tanning performance of PILs/MOF-LDH-Zr may be due to the multi-point cross-linking of –COOH, imidazole groups, and metallic zirconium. The conductive properties of PANI and the porous network structure of leather are helpful to realize electromagnetic shielding of the leather. Interestingly, after 1000 bending tests, more than 99% of the shielding effectiveness (SE) could be retained. As such, an effective and powerful strategy is proposed to construct flexible electromagnetic shielding material based on an eco-friendly chrome-free tanning approach.