Carbon Nanotube Coated Textile Sensors with Ultrahigh Sensitivity for Human Motion Detection

Highly sensitive stretch sensors are developed by coating knitted fabrics with carbon nanotubes. An innovative electrophoretic deposition approach is used to deposit a thin and conformal carbon nanotube coating on a nylon-polyesterspandex knitted fabric. The carbon nanotube coating is chemically bonded on the surface of the fibers and creates an electrically conductive network. As a result, these sensors display piezoresistivity; that is, the resistance of the sensor changes due to mechanical deformation. First, the sensing response under tension is characterized using mechanical testing equipment. The sensors are then integrated into compression knee sleeves to investigate sensing response due to knee flexion. When the sensing fabric is stretched, an increase in electrical resistance is observed due to change in the microstructure of the knitted fabric and because of the piezoresistivity of the coating. Under knee flexion, a resistance change of over three thousand percent is detected. The carbon nanotube coated knitted fabrics as flexible stretch sensors have wide-ranging applications in human motion analysis.