Highly stretchable and robust textile-based capacitive mechanical sensor for human motion detection

Mechanically stretchable capacitive sensors are extremely promising for applications in continuous health-monitoring. Typical capacitive sensors, made from polymer and thin metal film supporters, lack interfacial adhesion or chemical bonding and have intrinsically low stretchability. Moreover, the performance of most sensors is critically affected by the conformity mismatch at the electrode and dielectric layer interface during high mechanical deformation. Many mechanical sensors have limited practical applications due to significant hysteresis, low sensitivity, and lack of reproducibility. Herein, we develop a textile-based capacitive mechanical sensor by utilizing titanium carbide-based MXene (Ti3C2Tx) to fabricate conductive textiles and a composite film of polystyrene (PS) fibers and ecoflex silicone as a dielectric layer. Ti3C2Tx showed strong bonding with the fabric owing to its rich surface chemistry, hydrophilicity, and large surface area. The MXene-coated fabric and integration of the composite film make the sensor mechanically stretchable, thus improving its sensitivity, response time, and stability. The sensor showed negligible hysteresis (similar to 0.2) and demonstrated a high sensitivity of 1.11 when stretched to 100 % elongation and 13.02 kPa(-1) when squeezed at a pressure of 200 kPa and excellent cyclic stability (1000 cycles). The sensor was further utilized for the detection of human motion when specific body movements were performed.

Automated summary

Mechanically stretchable capacitive sensors have great potential for continuous health-monitoring. A textile-based capacitive sensor was developed using titanium carbide-based MXene (Ti3C2Tx) to fabricate conductive textiles and a composite film of polystyrene (PS) fibers and ecoflex silicone as a dielectric layer. The sensor showed excellent performance in terms of sensitivity, response time, and stability, and was able to detect human motion accurately.