A\nStretchable Strain-Insensitive Temperature Sensor\nBased on Free-Standing Elastomeric Composite Fibers for On-Body Monitoring\nof Skin Temperature

Abstract

To realize the potential\napplications of stretchable sensors in\nthe field of wearable health monitoring, it is essential to develop\na stable sensing device with robust electrical and mechanical properties\nin the present of varying external conditions. Herein, we demonstrate\na stretchable temperature sensor with the elimination of strain-induced\ninterference via geometric engineering of the free-standing stretchable\nfibers (FSSFs) of reduced graphene oxide/polyurethane composite. The\nFSSFs were formed in serpentine structures and enabled the implementation\nof a strain-insensitive stretchable temperature sensor. On the basis\nof the controlled reduction time of graphene oxide, we can modulate\nthe response and thermal index of the device. These results are attributed\nto the variation in the density of oxygen-containing functional groups\nin the FSSFs, which affect the hopping charge transport and thermal\ngeneration of excess carriers. The FSSF temperature sensor yields\nincreased responsivity (0.8%/°C), stretchability (90%), sensing\nresolution (0.1 °C), and stability in response to applied stretching\n(±0.37 °C for strains ranging from 0 to 50%). When the sensor\nis sewn onto a stretchable bandage and attached to the human body,\nit can detect the temperature changes of the human skin during different\nbody motions in a continuous and stable manner.