A waterproof and breathable textile pressure sensor with high sensitivity based on PVDF/ZnO hierarchical structure

Smart wearable devices based on piezoelectric effect are widely used, but it is a great challenge to ensure the breathability and waterproof of piezoelectric devices. Therefore, we use conductive fabric (CF) as electrode material. ZnO nanorods (NRs) were grown on one side of one CF, and electrospun PVDF nanofiber membrane was sandwiched between the CF with ZnO NRs and the other CF. Attributed to this structure, the pressure sensor has waterproof property and maintains good breathability. Furthermore, the sensor with the ZnO NRs/PVDF hierarchical structure piezoelectric layer can generate an output voltage of 1.60 ± 0.08 V at 150 kPa, which is more than 10 times higher than that of pure PVDF nanofiber membrane, and has a sensitive linear response in the wide range of 3–150 kPa (11.07 mV kPa−1). Moreover, after the sensor had experienced 3600 cycles of pressing, the output voltage basically remained unchanged. In addition, sliding on the sensor at a certain pressure can produce regular fluctuating signals, and the FEM is used to explain the principle of this process. Benefiting from the unique properties, the sensor can be installed on clothes to monitor the environment in real time like wind or rainfall.