Phase separation-regulated fabrication of MXene/PVA cryogel sensor with effective electromagnetic interference shielding

Multifunctional hydrogels with desirable mechanical properties have attracted extensive attention in flexible electronic devices. Herein, tough and robust Ti3C2Tx MXene/polyvinyl alcohol (PVA) composite cryogel with excellent flexibility is prepared via a cyclic freeze–thaw (F-T) method. The morphological and crystalline structure of the composite cryogel is regulated by the phase separation process during fabrication, which greatly contributes to the enhanced mechanical properties. The highly flexible and stretchable MXene/PVA cryogel exhibits sensitive and reliable responses to deformations, demonstrating promising application in the detection of human motions and smart coding. Furthermore, the composite cryogel presents a high absorption-dominated electromagnetic interference (EMI) shielding effectiveness of 25 dB at an ultralow MXene loading of 0.04 wt%, which is ascribed to the synergetic effect of its tunable porous structure and water-rich environment. These findings provide valuable insights into the design and fabrication of high-performance multifunctional hydrogels.