摘要
The low-cost and easily fabricated flexible tubular sensor can detect both axial and radial pressure, expanding its application in human health monitoring and disease diagnosis. This paper intensively investigated the effects of nanofiber arrangements on its performance. When compared with those based on unordered or axially ordered fiber, results show that radially ordered fiber can not only help strengthen the structural integrity of the sensor but also provide a more efficient conduction path for conductive materials, thereby improving response speed and accuracy. By comparing the device performance with different conductive materials, graphene with high conductivity and mechanical flexibility was proved to further enhance the sensitivity. A high-performance flexible tubular sensor was successfully achieved with axially ordered polycaprolactone (PCL) fiber as substrate and graphene as the conductive material. The sensor exhibits high sensitivity under large deformations (GF=6.07, 0–200 % strain), fast rapid response (255 ms), excellent durability (>4000 cycles), and good sweat performance. It has been smoothly used to monitor precise joint bending angles and lower limb motion states, providing effective information in neurodegenerative diseases diagnosis (e.g. Parkinson and stroke) and rehabilitation. Moreover, the multi-channel sensing system has been further applied to concurrently monitor respiratory and eye movement signals during sleep, which help effectively and comfortably identified sleep apnea syndrome.