PDA@MWCNTs/PEDOT:PSS enhanced polyacrylamide hydrogel for electromagnetic interference shielding, sensing, and infrared stealth applications

With technological advancement, electromagnetic interference (EMI) waves have begun to compromise equipment performance and human health, prompting significant interest in hydrogel electromagnetic shielding materials. In this study, a multifunctional EMI-shielding hydrogel was prepared via the hydrothermal method by incorporating dopamine-modified multi-walled carbon nanotubes (PDA@MWCNTs) and poly(3,4-ethylenedioxythiophene)-poly (polystyrene sulfonate) (PEDOT:PSS) into a polyacrylamide (PAM) matrix, enabling the formation of a conductive network within the hydrogel. This composite hydrogel exhibits an electromagnetic shielding performance of 39.72 dB in the 8.2–12.4 GHz frequency range, effectively attenuating electromagnetic waves, while maintaining a compressive strength of 3.69 MPa. Additionally, it exhibits infrared invisibility capabilities, maintaining a surface thermal equilibrium temperature of 52.2°C on a heating plate near 80°C. It also demonstrates outstanding motion detection sensing performance, capable of stable and repeatable resistive signal output. This study provides an effective strategy for preparing materials that simultaneously possess EMI shielding, sensing, and infrared invisibility functions.