Flexible Capacitive Pressure Sensors for Wearable Electronics

Flexible pressure sensors have attracted more and more attention recently due to their broad applications, such as electronic skin and wearable electronics for health monitoring. Among them, capacitive flexible pressure...

Rational Design of a Novel Highly Folding-tolerable Edgewo-rthia Chrysantha Lindi-derived Substrate for Versatile Flexible Pressure Sensors

Cellulose-based composites with superior mechanical and electrical properties are highly desirable for a sustainable and multifunctional substrate of flexible electronics. However, their practical application is hindered by the lack of superflexible cellulose-based composites to fabricate ingenious flexible electronics with considerable robustness. Here, cellulose derived from underutilized biomass (Edgewo-rthia chrysantha Lindi, ERCL) was composited with highly-conductive silver nanowires (AgNWs) through a general papermaking process. Benefiting from the interactions between cellulose and AgNWs including hydrogen bonding and van der Waals force, the composite presented superb electrical conductivity (> 27000 S/m) and flexibility (folding times ≥1110). By employing it as the substrate of flexible pressure sensors (FPSs) through layer-by-layer assembly, improved sensitivity (Gauge Factor=846.4), rapid response (0.44 s), and excellent stability (≥2000 folding cycles) were demonstrated. Impressively, the novel FPS could monitor human motions, including finger bending, elbow flexion, speaking, and pulse, suggesting its great potentials in emerging flexible electronics.

Flexible and Transparent Pressure Sensor Based on CNTs Film Microstructure

In recent years, capacitive flexible pressure sensors have been widely studied in electronic skin and wearable devices. The traditional capacitive pressure sensor has a higher production cost due to micro-nano machining technology such as lithography. This paper presents a flexible transparent capacitive pressure sensor based on a PDMS/CNT composite electrode, simple, transparent, flexible, and arrays without lithography. The sensitivity of the device has been tested to 0.0018 kpa -1 with a detection range of 0-30 kPa. The sensor is capable of rapidly detecting different pressures and remains stable after 100 load-unload tests.

High sensitivity and broad detection range flexible capacitive pressure sensor based on rGO cotton fiber for human motion detection

Recently, flexible pressure sensors have attracted considerable interest in electronic skins, wearable devices, intelligent robots and biomedical diagnostics. However, the design of high sensitivity flexible pressure sensors often relies on expensive materials and complex process technology, which greatly limit their popularity and applications. Even worse, chemical-based sensors are poorly biocompatible and harmful to the environment. Here, we developed a flexible capacitive pressure sensor based on reduced graphene oxide (rGO) cotton fiber by a simple and low-cost preparation process. The environmentally friendly sensor exhibited a comprehensive performance with not only ultra-high sensitivity (up to 15.84 kPa-1) and a broad sensing range (0-500 kPa), but also excellent repeatability (over 400 cycles), low hysteresis (≤11.6%), low detection limit (<0.1 kPa) and wide frequency availability (sensitivity from 19.71 kPa-1 to 11.24 kPa-1, frequency from 100 Hz to 10 kHz). Based on its superior performance, the proposed sensor can detect various external stimuli (vertical stress, bending and airflow) and has been successfully applied for facial expression recognition, breathing detection, joint movement and walking detection, showing great potential for application in artificial electronic skin and wearable healthcare devices.