High-Sensitivity Flexible Strain/Temperature Sensor Based on Multi-Walled Carbon Nanotube/Graphene/Vanadium Dioxide/Silicone Rubber Composites

Abstract

As wearable electronics advance toward the development of emerging sensing materials, high-performance integration, and intelligent applications, there is a growing demand for a single flexible sensor capable of comprehensively sensing environmental or physiological conditions. However, achieving high strain sensitivity and precise temperature monitoring remains a significant challenge for flexible dual-mode sensors. Inspired by fish scale textures, a biomimetic structure for a fish-scale-inspired flexible strain/temperature sensor (FSIFSTS) was proposed in this paper. The sensing layer of the FSIFSTS is fabricated as a nanocomposite consisting of multiwalled carbon nanotubes, graphene, and vanadium dioxide within a silicone rubber matrix. FSIFSTS features a 100% strain detection range and a low strain detection limit of 0.5%, along with 6500 cycles of durability within a 40% stretching range. In terms of temperature sensing, FSIFSTS exhibits a high sensitivity of −1.04% °C–1, ultrahigh linearity of 0.9962, and high temperature resolution of 0.5 °C within the 20–90 °C range. Owing to strain and temperature sensing capabilities, FSIFSTS can be applied not only to monitoring human joint movement and guiding rehabilitation training for patients with joint injuries but also to hot compress, high-temperature warnings, and gesture recognition for grasping. Therefore, FSIFSTS shows great potential in fields such as embodied intelligent robot, personalized medical assistance, and real-time human–machine interaction.