Construction of natural fiber/polyaniline core-shell heterostructures with tunable and excellent electromagnetic shielding capability via a facile secondary doping strategy

Core-shell heterostructures with tunable and superior electromagnetic interference (EMI) shielding capability are in high demand in modern smart electronics. Here, natural bagasse fiber/polyaniline (BF/PANI) core-shell composites were selected as the model heterostructures. It was demonstrated that both electrical characteristics and electromagnetic parameters of BF/PANI heterostructures can be easily tailored via a secondary doping strategy. High doping rate, large crystallite size, and extended linear PANI backbone contribute to the enhanced conductivity. Among five different re-doping acids, dodecylbenzenesulfonic acid re-doped heterostructure possesses a maximum conductivity of 6.27 S/cm. High interface polarization, capacitor-like structure, strong skin effect, and large attenuation constant contribute significantly to achieving an excellent shielding capability of 37.72 dB. Theoretical calculations reveal that absorption are remarkably improved by multiple reflection. Strong absorption behavior and power analysis confirm the absorption-dominated shielding mechanism. Taken together, these understandings will lead to a rational design of PANI-based heterostructures to achieve adjustable, superior shielding capabilities.