Biomimetic Gradient Microstructures Enable Stable, High-Sensitivity Pressure Sensing From Pa to MPa

Flexible pressure sensors are often evaluated over only a limited portion of their nominal operating range, making it difficult to simultaneously achieve high-sensitivity, ultrawide- range detection, and reliable signal resolution under large preloads within a single device. Here, we present a geometry-guided strategy for stable pressure sensing from Pa to MPa based on a biomimetic daisy-inspired gradient hemispherical array. By integrating finite-element-analysis-guided optimization with an interpretable simulation-trained surrogate model, the multilevel gradient microstructure is rationally engineered to regulate compressibility and contact-area evolution, thereby mitigating capacitive saturation and extending the accessible pressure range. The resulting iontronic sensor delivers a consistently high sensitivity exceeding 122 kPa −1 over 0–2555 kPa, together with an ultrahigh sensitivity of 1864 kPa −1 in the low-pressure regime (0–61 kPa) and a low detection limit of 7.6 Pa. The device further shows fast response/recovery times below 5 ms, stable operation under repeated loading, and reliable pressure resolution even under MPa-level preloads. Beyond device performance, the surrogate-model interpretation reveals the key multilevel design rules governing the sensing response, establishing a generalizable framework that links bioinspired geometry, interfacial mechanics, and pressure-sensing behavior. This integrated structure-mechanism-modeling strategy provides a practical route toward next-generation ultrawide-range flexible sensors for wearable electronics and human-machine interfaces.