Hierarchical Network Enabled Flexible Textile Pressure Sensor with Ultrabroad Response Range and High-Temperature Resistance.

Thin, lightweight, and flexible textile pressure sensors with the ability to detect the full range of faint pressure (<100 Pa), low pressure (≈KPa) and high pressure (≈MPa) are in significant demand to meet the requirements for applications in daily activities and more meaningfully in some harsh environments, such as high temperature and high pressure. However, it is still a significant challenge to fulfill these requirements simultaneously in a single pressure sensor. Herein, a high-performance pressure sensor enabled by polyimide fiber fabric with functionalized carbon-nanotube (PI/FCNT) is obtained via a facile electrophoretic deposition (EPD) approach. High-density FCNT is evenly wrapped and chemically bonded to the fiber surface during the EPD process, forming a conductive hierarchical fiber/FCNT matrix. Benefiting from the large compressible region of PI fiber fabric, abundant yet firm contacting points and high elastic modulus of both PI and CNT, the proposed pressure sensor can be customized and modulated to achieve both an ultra-broad sensing range, long-term stability and high-temperature resistance. Thanks to these merits, the proposed pressure sensor could monitor the human physiological information, detect tiny and extremely high pressure, can be integrated into an intelligent mechanical hand to detect the contact force under high-temperature.

Highly Sensitive and Wide Linear-Response Pressure Sensors Featuring Zero Standby Power Consumption under Bending Conditions.

The ability of a flexible pressure sensor to possess zero power consumption in standby mode, high sensitivity, and wide linear-response range is critical in real flexible matrix-based scenes. However, when the conventional flexible pressure sensors are attached on a curved surface, a pseudosignal response is generated because of the normal stress, resulting in a short linear-response range. Here, a flexible piezoresistive pressure sensor with high performance, zero standby power consumption is demonstrated. The flexible pressure sensor is fabricated from polydimethylsiloxane (PDMS)/carbon black (CB), patterned polyimide (PI) spacer layer, and laser-induced graphene (LIG) interdigital electrodes. Benefiting from the hierarchical structure and sufficient roughness of PDMS/CB and LIG interdigital electrodes, the proposed pressure sensors (PDMS/CB/PI/LIG) exhibit high sensitivity (43 kPa-1), large linear-response range (0.4-13.6 kPa), fast response (<40 ms), and long-term cycle stability (>1800 cycles). The resulting pressure sensor also features zero standby power consumption merit under certain bending conditions (bending angle: 0-5o). Furthermore, the effect of the hole diameter of the PI spacer layer on the performance of the pressure sensors is experimentally and theoretically investigated. As a proof of concept, a bioinspired artificial haptic neuron system has been successfully equipped to modulate the number of lit LED lights. The proposed high-performance pressure sensor has promising potential to be used in flexible and wearable electronics, especially for the applications in actual flexible matrix-based scenes.