Hydrogel Stack-Tailored Logics and High-Fidelity Multimodal Sensors Promoted by Precisely Evaluated Ionic Migration

Self-powered flexible sensors represent indispensable components in tactile sensing and wearable electronic systems. In biological organisms, intracellular and extracellular ion transport underpin the precise perception, transmission, and processing of tactile stimuli. Inspired by these natural mechanisms, four types of self-powered multifunctional sensors were developed based on the controlled motion of ions within cationic poly(diallyldimethylammonium chloride) and anionic sodium polystyrene sulfonate ionomers. The sensors exhibit a p-n junction configuration, where a depletion layer is established at the ionomer interface. Through the incorporation of 2D MXenes and 1D carbon nanotubes (CNTs), the electrical conductivity was optimized, yielding an open-circuit voltage of approximately 75 mV and a short-circuit current density of ∼67 µA cm^{- 2}. The distinct rectification behavior (ratio ≈ 8.8) enables logic circuit functionality, while the tunable assembly of sensing units into arrays allows precise discrimination of compression, bending, and directional stress stimuli. Unlike conventional pressure-sensing arrays, each unit in the present system displays unique sensing characteristics. This work offers a new paradigm for the rational design of high-performance, self-powered ionic sensors for next-generation flexible and wearable electronics.