Anti-drying, anti-freezing and super-elastic MXene/gelatin hydrogels for electromagnetic shielding and pressure sensing

Abstract

Conductive hydrogels with water-enriched pores have shown great potential in electromagnetic wave protection and flexible wearable electronics. However, hydrogel with high water content often results in some challenges such as water loss and low-temperature freezing. In this study, porous gelatin/ChCl/MXene Ti₃C₂T_x (GCM) hydrogels were prepared via a facile one-pot method. The introduction of ChCl forms abundant hydrogen bonds in GCM hydrogels, which endows the hydrogels long-term anti-drying (30 days) and anti-freezing abilities (-30 °C). Due to the synergistic effects of the porous structure, highly conductive MXene and water molecules, the electromagnetic interference (EMI) shielding effectiveness (SE) reach up to 108 dB in the X-band. Significantly, the effect of water molecules on EMI SE is quantified by adjusting the water content in hydrogel. Moreover, the gelatin-based hydrogel exhibits super-elasticity (0.25 MPa at 80% strain) and demonstrates no significant decrease in EMI SE after 500 compression cycles. Finally, the excellent pressure-sensing properties of GCM hydrogel enable sensitive and reliable detection in human motion and smart coding. Therefore, the developed GCM hydrogel demonstrates promising application prospects in the fields of EMI shielding and sensing for wearable electronic devices.