3D printed organohydrogel-based strain sensors with enhanced sensitivity and stability via structural design

Abstract Organohydrogel-based strain sensors are gaining attention for real-time health services and human-machine interactions due to their flexibility, stretchability, and skin-like compliance. However, these sensors often have limited sensitivity and poor stability due to their bulk structure and strain concentration during stretching. In this study, we designed and fabricated diamond-, grid-, and peanut-shaped organohydrogel based on positive, near-zero, and negative Poisson’s ratios using digital light processing (DLP)-based 3D printing technology. Through structural design and optimization, the grid-shaped organohydrogel exhibited record sensitivity with gauge factors of 4.5 (0–200% strain, ionic mode) and 13.5/1.5 × 10 ⁶ (0−2%/2%−100% strain, electronic mode), alongside full resistance recovery for enhanced stability. The 3D-printed grid structure enabled direct wearability and breathability, overcoming traditional sensor limitations. Integrated with a robotic hand system, this sensor demonstrated clinical potential through precise monitoring of paralyzed patients’ grasping movements (with a minimum monitoring angle of 5°). This structural design paradigm advanced flexible electronics by synergizing high sensitivity, stability, wearability, and breathability for healthcare, and human-machine interfaces.