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 Ti3C2Tx (GCM) hydrogels were prepared via a simple, scalable one-pot method. The introduction of ChCl forms abundant hydrogen bonds in GCM hydrogel, which endows the hydrogel 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 effects of water molecules on EMI SE are quantitatively identified by controlling the water content in the GCM hydrogels. Moreover, the gelatin-based hydrogel exhibits super-elasticity (0.25 MPa at 80% strain) and demonstrates no significant decrease in EMI SE after 100 compression cycles. Finally, the excellent pressure-sensing capabilities 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.

Keywords: super-elastic, anti-drying, MXene/gelatin hydrogel, EMI shielding, pressure sensing