The embedded microscopic sensor is able to recognize local motion through the stretching of the woven yarns that are treated with graphene nanoplatelets that can read the body's activity. Such sensors, say the researchers, may pave the way for smart clothing that can monitor human movement, as well as impact composites manufacturing and health-monitoring industries.
"Microscopic sensors are changing the way we monitor machines and humans," says engineering Professor Mina Hoorfar, lead researcher at the Advanced Thermo-Fluidic Lab at UBC's Okanagan campus. "Combining the shrinking of technology along with improved accuracy, the future is very bright in this area."
The sensor is based on piezo-resistivity, which produces a change in the electrical resistivity of a semiconductor or metal when mechanical strain is applied. Such sensors, say the researchers, have shown promise in detecting human movements and can be used for heart rate monitoring or temperature control.
The researchers' low-cost, sensitive, and stretchable yarn 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.
While potential applications include smart clothing, say the researchers, the sensor can also monitor deformations in fiber-reinforced composite fabrics currently used in advanced industries such as automotive, aerospace, and marine manufacturing. According to the researchers, the stretchable composite sensor has also shown a high sensitivity and can detect small deformations such as yarn stretching, as well as 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, eventually, say the researchers, making 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.
"Advanced textile composite materials make the most of combining the strengths of different reinforcement