Fabrication and application of a flexible piezoresistive pressure sensor with a hollow-carved structure

Pressure sensors are widely used in the field of clothing pressure testing, however, the current pressure sensors are not well-suited for curved surfaces of the human body, and their measurement accuracy is inadequate for assessing clothing pressure during human motion. In this work, a flexible piezoresistive sensor featuring a sandwich-type structure, wherein a carbon fiber (CF)/Thermoplastic polyurethane (TPU) blend film is employed as the pressure-sensitive layer and copper foil wire utilized as the electrode layers to cover both upper and lower surfaces of the pressure-sensitive layer is reported. Simultaneously, the pressure sensitive layer and electrode layers of the sensor undergo etching to acquire a hollow-shaped structure. The hollow-carved sensor exhibits excellent adaptability to curved surfaces, suitable sensing range (1-4.5 kPa), great sensitivity (10.091 kPa^-1), and fast response/recovery time (400 ms/300 ms). Furthermore, we showed that the hollow-carved sensor could be applied for clothing pressure testing of the human body during motion, even when attached to curved surfaces.