Nano Silver-Deposited Cotton Textile Core with Carbon Nanostructure-Filled Shell for Suppression of Electromagnetic Radiation Via Absorption-Reflection-absorption

Modern communication technologies require new materials with uncompromising electromagnetic interference (EMI) shielding. To this end, dispersing nano-flakes of functional particles in a polymer matrix is not amenable to meeting the stringent requirements of EMI shielding. Hence, herein, a multilayered architecture is proposed with a unique strategy of the 'absorbing-reflecting-absorbing' approach. This offers enhanced attenuation with the right choice of the constituting layers. We report a smart textile consisting of a reflecting core made from 'mussel -inspired' seeding of silver nanoparticles on cotton fabric (Ag-CF) and an 'absorbing shell' made of a solvent-free coating consisting of carbonaceous nanoparticles like carbon nanofibers (CNF) and graphene nanoplatelets (GNP). The Ag-CF was prepared by polydopamine-assisted deposition-a green and safe method compared to the other existing methods. This work highlights the optimization of the deposition process for seeding time and the synergistic improvements in shielding effectiveness (SE) using CNF and GNP that give maximum EM attenuation. We observed both the Ag-CF and the CNF/GNP coating work to enhance thermal stability, ultraviolet (UV) blocking, and microwave shielding. The developed multifunctional textile showed a microwave SE of-50 dB, 99.99% UV blocking with exceptionally high values of UV protection factor (UPF) - 175, and a limiting oxygen index of 27%, demonstrating its high thermal stability. The developed hybrid textile shows excellent heat dissipation properties by cooling to 34 degrees C from 93 degrees C in just 60 s. It also proved to be a robust material showing no change in properties against washing-laundering cycles. To gain mechanistic insight into this approach, instead of seeding Ag on CF, it was seeded directly onto the carbon nanostructures (to yield Ag@CNF and Ag@GNP, respectively) and coated on the fabric. It was observed that layer positioning in the smart textile plays a crucial role in maximizing attenuation. The smart textile with an absorbing-reflecting-absorbing strategy at-tenuates the incoming EM radiation much more efficiently than dispersing the hybrid structures (like Ag@CNF and Ag@GNP) on the textile.