Flexible pressure sensor based on polystyrene foam with superelasticity and ultra-wide range

The use of flexible pressure sensors has significantly advanced and improved human life. However, several issues are hindering their applicability such as the difficulty to achieve high sensitivity over a wide pressure measurement range. Herein, a one-step foaming method and hydrothermal approach were used to fabricate a three-dimensional conductive porous foam comprising polyurethane, carbon nanotube, and polyaniline. The sensor exhibits excellent electrical conductivity due to its cellular foam structure, while its high durability enables a large response output across an extremely broad range (0–30 000 kPa). The sensor also exhibits exceptional stability over 1000 loading/unloading cycles, a fast response time of 80 ms, and high sensitivity of 0.019 53 kPa⁻¹ (0–200 kPa), 0.126 48 kPa⁻¹ (200–5000 kPa), and 0.038 85 kPa⁻¹ (5000–30 000 kPa). Furthermore, rational material selection and structural design allows the sensor to monitor low- to high-signal stimuli, thereby providing a reference for the design of other large-scale sensors.