A novel self-supported printed flexible strain sensor for monitoring body movement and temperature

A novel self-supported printed strain sensor was successfully screen printed using silver (Ag) ink on a water-soluble sacrificial polymer layer, which was pre-coated on a flexible polyethylene terephthalate (PET) film, for monitoring body movement. The printed sensor, along with the polymer layer, was peeled off the PET film and transferred onto the wrist. Then the sacrificial layer was dissolved with water. The capability of the printed sensor for monitoring the movement of the body was investigated by subjecting the sensor towards different inward and outward bending of the wrist. The average resistance of the sensor decreased by approximately 10 % for multiple inward bending and attained its base resistance, of 29 Ω, when the wrist was brought back to the original relaxed position. It was also observed that the resistance of the sensor increased by 0.1 Ω when the temperature was increased by 1 °C, thereby demonstrating the feasibility of the device to be used as a temperature sensor. The design, fabrication and response of the self-supported printed strain sensor is analyzed and presented in this paper.