Bioinspired Soft Pressure Sensors with Interlocked Structures Based on 3D Printing Methods

With the rapid development of microelectronics technology, piezoresistive sensors have been widely used in various fields. To meet the needs of different application scenarios, it is essential to design various types of microstructures to improve the sensitivity and force detection range of the sensors. Human skin effectively senses external pressure and provides important tactile feedback when touching and manipulating objects. In this paper, inspired by human skin, a flexible pressure sensor has been successfully designed using 3D printing technology, which uses two kinds of materials with different rigidity to fabricate four microstructures: single-layer solid, single-layer hollow, double-layer solid interlocking, and double-layer hollow interlocking, suitable for various detection scenarios. A detailed comparison of the performance of the different sensors reveals that the double-layer solid interlocking structure sensor (R1) fabricated with rigid materials exhibits excellent sensitivity (2.94 kPa–1) and a wide pressure detection range (<350 kPa) with fast response and recovery times, as well as excellent stability. Meanwhile, the double-layer solid interlocking structure sensor (F1) made of flexible material also exhibits high sensitivity (6.93 kPa–1) and excellent stability in the low-pressure range of <71 kPa. To further validate the excellent performance of these sensors, we applied the R1 and F1 sensors to a variety of different force detection scenarios, including clamp gripping, foot stepping, dumbbell pushing, shoulder-to-strap contact, finger pressing, and knocking processes, respectively. Such flexible pressure sensors with adjustable thresholds have obvious advantages in both small and large pressure detection scenarios.