Easily Fabricated Flexible Pressure Sensor with Angelfish-Structured ZnO/SR Dielectric Layer for Human–Machine Interaction

The rapid advancement of human-machine interaction (HMI) technologies and smart wearable devices has driven an increasing demand for high-performance flexible tactile and pressure sensors. Herein, we propose a unique dielectric layer design inspired by the geometry of the angelfish. A bionic angelfish-structured mold was fabricated by using three-dimensional (3D) printing. A high-performance composite dielectric layer was developed by incorporating zinc oxide (ZnO), a piezoelectric material characterized by its high dielectric constant and low dielectric loss, into silicone rubber (SR). This approach ensured sensor stability while significantly reducing the Young's modulus. The developed flexible capacitive pressure sensor demonstrated enhanced overall performance, including a broad pressure detection range of 0-400 kPa, an exceptionally low detection limit of 0.8 Pa, a high sensitivity (∼5.096 kPa^-1 in the range of 0-1 kPa), along with sensitivities of 1.081 kPa^-1 (1-10 kPa) and 0.053 kPa^-1 (10-400 kPa), as well as rapid response/recovery times (∼87.5, ∼62.5 ms). Notably, the sensor maintained stable performance over 6000 testing cycles, indicating its long-term durability. Furthermore, leveraging these performance advantages, the sensor's innovative applications in advanced HMI and pressure visualization open novel possibilities for interactive technologies. The sensor also effectively captures pressure variations during hand movements in wearable sensing, demonstrating its practical potential for biomechanical monitoring.