Microstructured Polyelectrolyte Elastomer-Based Ionotronic Sensors with High Sensitivities and Excellent Stability for Artificial Skins

High-performance flexible pressure sensors are highly demanded for artificial tactile sensing. Using ionic conductors as the dielectric layer has enabled ionotronic pressure sensors with high sensitivities owing to giant capacitance of the electric double layer (EDL) formed at the ionic conductor/electronic conductor interface. However, conventional ionotronic sensors suffer from leakage, which greatly hinders long-term stability and practical applications. Herein, a leakage-free polyelectrolyte elastomer as the dielectric layer for ionotronic sensors is synthesized. The mechanical and electrical properties of the polyelectrolyte elastomer are optimized, a micropyramid array is constructed, and it is used as the dielectric layer for an ionotronic pressure sensor with marked performances. The obtained sensor exhibits a sensitivity of 69.6 kPa^-1 , a high upper detecting limit on the order of 1 MPa, a fast response/recovery speed of ≈6 ms, and excellent stability under both static and dynamic loads. Notably, the sensor retains a high sensitivity of 4.96 kPa^-1 at 500 kPa, and its broad sensing range within high-pressure realm enables a brand-new coding strategy. The applications of the sensor as a wearable keyboard and a quasicontinuous controller for a robotic arm are demonstrated. Durable and highly sensitive ionotronic sensors potentialize high-performance artificial skins for soft robots, human-machine interfaces, and beyond.