CNT@CNF/MXene hydrogel with complete conductive network for flexible anti-freeze sensor and electromagnetic shielding

The rapid development of communication technologies and flexible human-computer interfaces, necessitates the fabrication of a strain sensor with high sensitivity and electromagnetic interference (EMI) shielding performance. The purpose is to monitor human movement and protection from electromagnetic damage. Herein, we prepared tough, conductive, and self-healing carbon nanotube@cellulose/MXene (CCM) acrylamide-based hydrogels to achieve the dual-functional applications of strain sensors and EMI shielding. The carbon nanotubes and cellulose self-assembled into conductive fibers. Then, the two-dimensional MXene nanosheets were interconnected through the conductive fibers while being cross-linked into a complete conductive network through the metal-ligand bonding of Zn²⁺. Owing to the excellent conductivity (9.64 S/m) of the CCM hydrogel and the non-covalent reversible interactions among the components, the composite hydrogel exhibited excellent tensile strain (~424 %), efficient self-healing ability (87.2 %), frost and water retention (T_c < -60 °C), and efficient shielding effectiveness (51.8 dB). Meanwhile, as a strain sensor, it also possessed excellent sensing performance such as high sensitivity (GF = 20.17), wide detection range (0 %-400 %), fast response time (~135 ms), and high stability (~500 cycles). These features provide an idea for the subsequent design of flexible sensing electronics with EMI shielding performance.