Composition‐Tuned Hydrogel Iontronic Patch With a Shared Electrode for Dual‐Mode Pressure and Moisture‐Electric Sensing in Wearable Health Monitoring

Vollständiger Abstract

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ABSTRACT Dual‐mode wearable patches usually stack discrete sensing and energy modules made from dissimilar materials, which increases thickness and limits skin conformability. Here we report a hydrogel iontronic patch, 1.56 mm thick, in which both pressure sensing and moisture‐electric signaling arise from a single H 3 PO 4 /ZnCl 2 /poly(vinyl alcohol) hydrogel by tuning the ZnCl 2 ‐to‐H 3 PO 4 ratio. The two functional layers share one Zn foil as a common internal electrode, merging two device stacks into a single compact unit while keeping the channels electrically independent. The pressure‐sensing layer delivers a sensitivity of up to 0.60 nF kPa −1 with a measurement range extending to 2 MPa with stable response across 10,000 cycles. The moisture‐electric layer generates about 0.8 V at 90% relative humidity and remains stable for over 100 h. The pressure channel captures arterial pulse, respiration, and joint motion, while the moisture channel tracks breathing‐ and perspiration‐related humidity. Coupled with a one‐dimensional convolutional neural network, the multichannel pressure output recognizes five representative tennis strokes, with cross‐subject validation on five additional volunteers achieving 92.8% mean accuracy, offering a material‐level route toward thinner, skin‐conformable wearable healthcare.