Flexible Pressure Sensors with Wide Linearity Range and High Sensitivity Based on Selective Laser Sintering 3D Printing

To achieve practical applications of flexible pressure sensors, good performance and scalable manufacturing processes are both desired. Here, flexible pressure sensors with excellent performance are fabricated via selective laser sintering (SLS). Having benefitted from the irregular microstructures generated in the powder sintering process, the sensors exhibit high sensitivity of 55 kPa(-1) in a wide linearity range of 100 kPa, and they maintain decent sensitivity (>10 kPa(-1)) over a high-pressure range (100-400 kPa), which is among the best results for flexible pressure sensors. The working mechanism of the sensor is finely revealed combining in situ observations and electrical simulations. The results demonstrate that electrical saturation (due to parasitic resistance) greatly affects the linearity range except for the geometric saturation of the microstructure. As a proof of concept, tactile, pulse, muscle stiffness, and plantar pressure tests are performed. The fast and stable responses of the sensor show its great potential for electronic skin, human-machine interface, and healthcare monitoring. Besides its excellent performance, the fabrication processes via SLS are compatible with fab-scale production and flexible customization, which pave new paths for the mass manufacturing and diversified applications of flexible pressure sensors in the future.