Flexible and self-healing tannic acid-Fe3O4@MXene-composited dual network hydrogel multifunctional strain sensor

In light of the exponential growth of flexible human-computer interactions and telecommunications, it is becoming increasingly important to develop a high-sensitivity strain sensor to monitor human movement. Herein, the biocompatible, adhesive, and flexible Tannic acid-Fe 3 O 4 @MXene-poly(methacryloxyethyl sulfobetaine/acrylamide) (TFM) hydrogel has been prepared to realize the dual-functional applications in strain sensitive sensor and electromagnetic interference (EMI) shielding. The polymer network and 2D conductive filler MXene together construct the conductive network inside the hydrogel. The interpenetrating network and hydrogen bond between poly(acrylamide) and poly(methacryloxyethyl sulfobetaine) chain enhance the mechanical property of hydrogel, which is also improved by the complexation between Fe 3 O 4 and the catechol groups of tannic acid. Benefiting from the excellent electrical conductivity (∼1.33 S/m) and mechanical property of the TFM hydrogels, the strain sensor displays compressive strain (∼77.6 %) and elongation (∼308.5 %), adhesion (∼16 kPa), compression sensitivity (∼42.6 Pa −1 ), gauge factor (GF = 2.38), and cyclic stability (∼50 cycles). TFM hydrogels can monitor strain distribution sensing, pulse beating and human movement detection. Moreover, the TFM hydrogel exhibits an absorption-predominant EMI shielding performance with an effective value of ∼25.2 dB. This work provides a new inspiration for the development of multifunctional hydrogels in the fields of artificial intelligence, human-computer interaction, and EMI shielding technology.