Mechanically Driven, Self-Powered Hydrogel Iontronics for Visualized Tactile Logic Gate Circuit

The modulation of ion transport underlies neuronal signal integration, yet achieving self-powered tactile logic based on ionic mechanisms remains challenging. Here we report a hydrogel iontronic platform that mimics neuronal threshold-triggered action potentials and enables mechano-driven, self-powered logic processing. A polyvinyl alcohol/polyacrylamide (PVA/PAM) double-network hydrogel with engineered geometric, mechanical, and impedance asymmetry exhibits pronounced nonlinear ion gating, delivering peak ionic current densities of ∼2 mA cm^{- 2} at 72.68 kPa (0.275 A m^-2 kPa^-1), exceeding state-of-the-art devices and orders of magnitude higher than conventional piezoionic systems. Molecular dynamics simulations reveal that interactions between NO₃ ^- and water molecules in hydrogel invert diffusion asymmetry, providing deterministic control over ionic transport. Electrolyte selection enables programmable switching between excitatory and inhibitory ionic outputs, allowing realization of four fundamental self-powered Boolean logic gates (OR, AND, NOR, and NAND) through simple series-parallel integration. Coupling triboelectric nanogenerators (TENG) enables real-time visualized tactile logic via LED outputs. This work advances hydrogel iontronics from passive sensing toward integrated perception-cognition, opening new routes for neuromimetic human-machine interfaces (HMI) and Internet-of-Things (IoT) systems.