Flexible Pressure Sensor With Co‐Optimized Sensitivity and Linearity Based on Gradient Toroidal Microstructures

ABSTRACT Flexible pressure sensors enable broad applications in human‐machine interactions (HMI), motion detection, healthcare monitoring, etc. However, structural stiffening‐induced signal saturation, which narrows the sensitivity and linear sensing range, is still a major challenge. To address these issues, this study presents a flexible pressure sensor based on gradient design of toroidal conductive layers that utilizes the area coverage between two facing conductive electrodes. The toroidal layer, composed of polydimethylsiloxane (PDMS) and carbon nanotubes (CNT), exhibits a progressive increase in contact area under external pressure, leading to a proportional enhancement in sensitivity. Meanwhile, the hierarchical toroidal geometry allows the conductive layer to sequentially engage with the electrodes from the upper to lower rings, thereby maintaining excellent linearity over an ultrawide pressure range. The results demonstrate a high sensitivity of 256.20 kPa ^{− 1} , an ultrawide linearity range of 0–1000 kPa, rapid response, and robustness under cyclic loading. Furthermore, the sensor can effectively detect various human motions, including finger, wrist, and foot movements. The results indicate that the optimized sensor architecture markedly enhances the electromechanical performance in linear sensing behavior. It is anticipated that this methodology provides a valuable reference for designing high‐performance flexible pressure sensors for HMI, motion monitoring, and electronic skin applications.