3-D Printed Fourth-Order Star-Like Negative Poisson’s Ratio Structure for High-Sensitivity Bionic Flexible Capacitive Pressure Sensor

Flexible pressure sensors have gained great attention for their application prospects in the field of wearable electronics and multidimensional human–machine interaction. We prepared a fourth-order star structure consisting of four arrow-like concave triangular models by 3-D printing. The starfish-inspired bionic capacitive pressure sensor can be obtained using such a dielectric layer with the negative Poisson's ratio (NPR) effect. The fabrication process, structural parameters, design principles, sensing mechanism, and performance of the fourth-order star-structure capacitive pressure sensor (FSCPS) are discussed in detail. The FSCPS features a wide pressure sensing range of 0–500 kPa, a low detection limit of 1.6 Pa, a sensitivity of up to 2.151 kPa $^{-{1}}$ over a range of 0–10 kPa, fast response/recovery times (55 and 60 ms) for pressure measurements, and good durability (~2000 cycles). The FSCPSs are integrated into a rubber glove to capture the electrical output generated by the gesture. The use of deep learning enables the recognition of different gestures, showing potential use in soft grasping and human–computer interaction. Our biomimetic manufacturing method can provide a strategy for fabricating flexible pressure sensors with high performance and low cost.