Hybrid Foam Pressure Sensor Utilizing Piezoresistive and Capacitive Sensing Mechanisms

The development of flexible and stretchable sensing for future applications, e.g., strain, force, and pressure, requires novel foam and foam-like structures with properties such as fast relaxation times, a wide linear response range, good sensitivity to different stimuli and repeatability, without compromising low-cost, simple and effective manufacturing methods, and excellent mechanical properties. We present a new type of hybrid foam pressure sensor that utilizes a combination of piezoresistive and capacitive sensor elements. The hybrid foam sensor shows a maximum pressure sensitivity of 0.338 kPa-1and a linear response of 0.049 kPa-1 in the piezoresistive and capacitive sensor elements, respectively, in the pressure ranges of80 kPa). Simultaneously, both the sensor elements can be used for impact measurements across a wide range of pressures up to ≥240 kPa. Thus, the concept of the hybrid foam sensor could be utilized widely for sensing of pressures, impacts, or even bending in various applications, e.g., wearable electronics.