Photopolymerized low-swelling hydrogels incorporating Mo-MXenes for EMI shielding applications

Abstract

The advancement of compact, durable, and highly integrated electronics dictates the need for effective shielding from electromagnetic interference (EMI). This study was focused on the synthesis and characterization of hydrogels designed for EMI shielding applications obtained by a straightforward photopolymerization-based strategy. Different concentrations of Mo₂Ti₂AlC3 (0.1 %, 0.2 %, and 0.4 wt %), and polypyrrole particles, which serve as electroconductive components, were incorporated into hydrogels with a semi-interpenetrated polymer network (sIPN) resulting from the photopolymerization of hydroxyethyl methacrylate (HEMA) and acrylic acid (AA) in the presence of polyvinyl alcohol (PVA). Ultrasonication pretreatment of Mo₂TiAlC₃ in polyvinyl alcohol improved intercalation and ensured uniform integration into hydrogel films. Characterization techniques, including SEM, TEM, FT-IR, mechanical tests, TGA, XRD, and EMI shielding measurements, provided valuable insights into the properties and performance of the MXenes-based hydrogels. These hydrogels exhibited high gel fraction values (>98 %) and reduced swelling, indicating an increased crosslinking density. The optimal dispersion of MXenes (0.1–0.2 wt %) in the hydrogel matrix resulted in enhanced mechanical performance and effective EMI shielding, with the Hgel-MX-0.1 % sample displaying the best EMI shielding efficiency. The presence of water in the hydrogels ensures uniform conductivity throughout the composite hydrogel matrix. This innovative approach highlights the potential of flexible materials like MXenes-based hydrogels for advanced technological applications, offering superior viscoelastic properties, mechanical stability, and effective EMI shielding.