A Flexible and Highly Sensitive Capacitive Pressure Sensor With Microstructured Dielectric TPU Layer Based on Mesh Fabric as Template

Flexible and highly sensitive capacitive pressure sensors have outstanding privileges, such as good stability, simple structure, low power consumption, small hysteresis, and low-temperature effect. However, their challenging preparation method is an obstacle to being industrialized. To address this issue, a simple and low-cost method has been proposed in the present work by which highly sensitive capacitive pressure sensors can be feasibly constructed. First, the thermoplastic polyurethane (TPU) layer was obtained by employing two-step replication and using the stainless-steel mesh fabric as a template. Then, the dielectric TPU layer was assembled with conductive fabric electrodes to form the capacitive pressure sensor. There is no need to apply expensive professional equipment with high precision during the formation process of the present capacitive pressure sensor as it is easy to control the microstructure of the TPU film by changing templates. Eventually, the microstructured dielectric TPU layer is prone to deform with external pressure, resulting in superior sensing performance of the sensor, such as high sensitivity of 0.182 kPa
$^{-{1}}$
, a short response time of 78 ms, a low detection limit of 15 Pa, as well as remarkable pressure resolution and good stability. This capacitive pressure sensor is also able to detect several human movements, such as finger bending, finger pressing, fist-clenching, and swallowing, indicating its applications in electronic skin, smart wearable, and human–computer interaction.