A low-cost sensor was developed that can be interlaced into textiles and composite materials, paving the way for smart clothing that can monitor human movement. The embedded microscopic sensor is able to recognize local motion through the stretching of woven yarns treated with graphene nanoplatelets that can read the body's activity.
The device uses a phenomenon called piezoresistivity — an electromechanical response of a material when it is under strain. These tiny sensors have shown great promise in detecting human movements and can be used for heart rate monitoring or temperature control.
The new research shows the potential of a low-cost, sensitive, stretchable yarn sensor. The sensor can be woven into Spandex material and then wrapped into a stretchable silicone sheath. This sheath protects the conductive layer against harsh conditions and allows for the creation of washable, wearable sensors. The sensors can also monitor deformations in fiber-reinforced composite fabrics currently used in automotive, aerospace, and marine manufacturing.
The low-cost, stretchable, composite sensor has also shown a high sensitivity and can detect small deformations such as yarn stretching and out-of-plane deformations at inaccessible places within composite laminates. Testing indicates that further improvements in its accuracy could be achieved by fine-tuning the sensor's material blend and improving its electrical conductivity and sensitivity. This can eventually make it able to capture major flaws like “fiber wrinkling” during the manufacturing of advanced composite structures such as those currently used in airplanes or car bodies.