Low-Temperature Bending Fatigue of NR Flexible Strain Sensor

Abstract

The natural rubber (NR) strain sensors are attracting attention due to their potential applications in electronic skin, soft robotics, and health monitoring. However, the bending effect on the fatigue performance of the NR sensor changed by the low temperature becomes a restriction factor to their application. Herein, the flexible carbon nanotubes (CNTs)-Ag nanoparticles-NR sensor is fabricated by one-pot route method, which show a sensitivity of up to 108 kPa−1 and a bending stability of more than 15 000 times at room temperature. The finite element (FE) results suggest that the NR/CNT interfacial cracks play different roles in the development of crack at various temperatures. At room temperature, the NR chain migration/diffusion and the destruction of the cation– $\pi $ interaction at the NR/CNT interfacial cracks can effectively enhance the fracture energy and inhibit the cracks propagation upon repeated bending. However, at low temperature, the migration/diffusion processes can be destroyed by the hardened crystals of NR molecular chains in the CNT/NR interfacial cracks, which accelerates the crack propagation and thus eventually deteriorates the NR sensor.