Buckling‐Driven Linearity in Flexible Capacitive Pressure Sensors Based on a Three‐Dimensional Dual‐Pore Polyurethane Structure

ABSTRACT Recent advances in 3D porous structures have been utilized in pressure sensing to improve sensitivity and pressure range owing to their deformability and compressibility. Sensitive pressure sensors using 3D porous structures have been used in advanced applications such as motion detection, human–machine interfaces, and bio‐signal monitoring. However, achieving both high sensitivity and linearity over a wide pressure range remains a critical challenge due to the intrinsic trade‐off between these two properties. In this study, we propose a soft pressure sensor based on a 3D dual‐pore polyurethane (DPPU) structure fabricated through a sugar‐templated molding and forming process. The dual‐pore architecture, comprising pores of different sizes and shapes, induces sequential buckling. Such buckling‐driven deformation generates local stress concentration within the pore columns, thereby changing the deformation behaviors. As a result, the sensor exhibits high sensitivity (0.245 kPa −1 ) and excellent linearity (R 2 = 0.985) over a wide pressure range, while maintaining outstanding mechanical robustness and reliability. Furthermore, its practical applicability is demonstrated through integration into bio‐signal monitoring devices—such as voice and pulse signals—and pressure sensor arrays embedded in smart insoles for real‐time gait phase analysis.