Double‐Domed Dielectric Foam with Engineered Modulus Gradient for Wide‐Range Linear Capacitive Pressure Transduction

Abstract

Abstract Flexible capacitive pressure sensors offer low‐power, skin‐compatible detection for wearables and human–machine interfaces, yet combining high sensitivity, linearity, and wide range is challenging. In this paper, a graded dielectric is created by laminating low‐k micro‐dome arrays onto a compressible high‐k porous foam, aligning permittivity and modulus gradients. This architecture steers the electric field from series to parallel as the applied force increases, preserving charge storage. The sensor delivers a sensitivity of 0.393 kPa −1 with strict linearity ( R 2 = 0.99) across 0–900 kPa. It resolves arterial pulses, breathing and joint motion while surviving impacts over 100 kPa, enabling “gentle‐touch‐to‐heavy‐grasp” monitoring. When mounted on a bidirectionally bending joint such as the wrist, the sensor generates opposite‐signed signals during flexion and extension, enabling error‐tolerant Morse‐code inputs. A four‐threshold mapping further enables proportional force feedback and multifinger grasp control in soft robotic hands. The robust, fast and repeatable gradient dielectric therefore furnishes a scalable platform for full‐spectrum wearable sensing, secure communication and low‐power haptic robotics.