Piezoionic copolymer ionogel with tunable hydrogen bond enables epidermal blood pressure analyzer

Self-powered sensors that directly convert mechanical stimuli into electrical signals hold promise for next-generation bio-integrated electronics, but their practical translation is hindered by low electrical output and poor mechanical properties. Herein, we present an engineered copolymer ionogel featuring piezoionic amplification and enhanced mechanical properties through optimization of the hydrogen bond network by inserting polyurea chains into poly(vinyl alcohol) (PVA). The optimized copolymer ionogel achieves a voltage output of 20 millivolts, which is 10 folds higher than conventional PVA ionogels. Exceptional stretchability (1510%), toughness (23.1 megajoules per cubic meter), and durability are also achieved. Integrated into a wearable epidermal sensor with a machine learning algorithm, the copolymer ionogel enables cuffless, noninvasive, and continuous blood pressure monitoring, achieving mean absolute errors of 5.9 millimeters of mmHg (mmHg; systolic) and 3.6 mmHg (diastolic), thereby satisfying the stringent grade A of British Hypertension Society standard. This hydrogen-bond optimization strategy provides an avenue for piezoionic amplification and demonstrates the practicality of high-performance ionogels for wearable health-monitoring devices, thereby advancing the development of next-generation wearable biomedical systems.