Construction of Fe3O4@ZIF-67 based flexible multifunctional hydrogels for electromagnetic interference shielding and strain sensing

Traditional electromagnetic shielding materials can no longer meet the rapidly growing demands of modern flexible electronic devices and advanced information technologies. Owing to their excellent flexibility, adhesion, stimuli responsiveness, and ease of processing and functional modification, hydrogels offer promising opportunities for developing flexible wearable electronic devices. In this study, PAM/CMC/Fe 3 O 4 @ZIF-67 multifunctional composite hydrogels were fabricated through a reverse-growth strategy combined with a one-pot polymerization method. First, flower-like Fe 3 O 4 microspheres were prepared via an ethylene glycol-assisted solvothermal method and subsequently coupled with ZIF-67 through a reverse-growth strategy to obtain the Fe 3 O 4 @ZIF-67 composite. Subsequently, the composites were introduced into a PAM/CMC-based three-dimensional network, forming a multifunctional hydrogel that integrates flexibility, high water content, and synergistic conductive–magnetic effects. The experimental results showed that the 3 mm-thick PCZF-2 hydrogels achieved an average EMI SE of 36.08 dB. It also exhibited a conductivity of 0.93 S m −1 , a compressive modulus of 398.0 kPa, a compressive strain of 64.1%, a water content of 625.72%, and a swelling ratio of 240.82%. The hydrogel also exhibited excellent adhesion capability and high sensitivity (GF = 1.40 within the strain range of 0–100%, R 2 = 0.995), enabling human–machine-interaction-friendly strain sensing. This study provides an effective strategy for constructing tough multifunctional materials with integrated electromagnetic interference shielding and strain-sensing functionalities. Functional Fe 3 O 4 @ZIF-67 composite fillers were constructed via a reverse-growth strategy and incorporated into a double-network composite hydrogel through a one-pot method. The synergistic effects of magnetic loss, dielectric loss, and multiple scattering induced by the fillers endow the material with excellent electromagnetic interference shielding performance. Meanwhile, the deformation-responsive conductive network enables highly sensitive human motion sensing, providing an effective pathway for the development of integrated flexible materials for electromagnetic protection and intelligent sensing. Download: Download high-res image (252KB) Download: Download full-size image