Hierarchical Structural-Interfacial Engineering with Dynamic Soft-Hard Cross-Linking Enables Full-Range, Ultrasensitive MXene Piezoresistive Sensors.

Abstract

Human tactile perception inspires flexible piezoresistive sensors, yet simultaneously achieving high sensitivity, a wide pressure range, and mechanical robustness remains challenging. Here, we report a hierarchical stress-regulation strategy that integrates multiscale surface microstructures with a dynamically cross-linked MXene/carboxymethyl cellulose/borax sensing network. Replicated microtopographies induce progressive and spatially distributed stress localization, while heterogeneous soft-hard cross-linking regulates nanoscale deformation through adaptive hydrogen bonding and rigid borate anchoring. This coupled structural-interfacial regulation generates abundant stress-concentrated sites, stabilizes conductive pathways, and enables continuous resistance modulation across a broad pressure spectrum. Consequently, the sensor exhibits ultrahigh sensitivity (774.48 kPa^-1), a wide working range (334.16 kPa), and fast response/recovery times (8.58/17.22 ms). It reliably captures both subtle physiological signals and large mechanical loads and further supports gesture recognition and robotic control when integrated with real-time feedback and machine learning. This work establishes a general framework for designing robust, full-range tactile sensors through hierarchical stress regulation.