Bioinspired Interfacial Engineering of Dual‐Nanocomposite Hydrogel for High‐Performance Strain Sensing With Exceptional Stretchability and Toughness

ABSTRACT Hydrogel‐based strain sensors are promising for wearable and bio‐integrated electronics, yet their performance is often constrained by the trade‐off between electrical conductivity, mechanical robustness, and long‐term stability. MXenes offer high conductivity but commonly suffer from mechanical fragility, oxidative degradation, and aggregation in hydrogels. Here, we report a bioinspired dual‐nanocomposite hydrogel (DCM) that leverages catechol chemistry inspired by mussel foot proteins, in which dopamine‐functionalized carbon nanotubes (DCNTs) serve as active interfacial bridges to couple MXene nanosheets. Distinct from conventional designs based on physical mixing, this strategy enables direct and robust interfacial coupling between nanofillers. Catechol‐mediated interfacial interactions enhance MXene dispersion and suppress oxidation, leading to the formation of DCNT‐MXene nanocomplexes that establish percolating conductive networks within a loosely crosslinked polymer matrix. The DCM hydrogel exhibits high conductivity (≈0.37 S m −1 ), ultrahigh stretchability (up to 1400% strain), and exceptional toughness (14.35 MJ m −3 ). As a strain sensor, it delivers a high gauge factor (GF) of up to 20.15 and reliably detects both subtle physiological signals and large‐scale body motions. Integration with machine‐learning algorithms further enables accurate speech recognition. This work establishes a general bioinspired interfacial design strategy for multifunctional hydrogel electronics.