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.