Biaxial Sinusoidal Superposition Interlocked Architecture with Asymmetric Modulus Distribution Enables High-Performance Flexible Capacitive Pressure Sensors for Tactile Sensing

Flexible pressure sensors (FPS) hold great promise for health monitoring and intelligent robotics, yet simultaneously achieving high sensitivity and a wide linear detection range remains a key challenge. Inspired by the continuous interlocked microridge structures and gradient stiffness distribution of the human epidermal-dermal layer, this work presents a flexible capacitive pressure sensor with a biaxial sinusoidal superposition interlocked architecture and asymmetric elastic modulus distribution, termed BASIS. The continuous interlocked configuration induces multipoint stress concentration at the initial low-pressure contact stage, ensuring high sensitivity in the low-pressure range, while the asymmetric elastic modulus design further extends the linear sensing range. Experimental results show that the BASIS achieves a peak sensitivity of 13.08 kPa-1 over a linear range of 0-525 kPa, with fast response and relaxation times of 50 ms and 81 ms, respectively. Benefiting from these merits, the sensor accurately captures weak physiological and motion signals such as respiration and joint bending. Furthermore, a tactile material recognition system constructed by integrating the sensor onto a six-axis robotic arm realizes the identification of six materials with an average accuracy of 98.94%. This work provides a new design paradigm for high-performance flexible pressure sensors and offers insights for advances in electronic skin.