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.