Design and Fabrication of a Four-Electrodes PVDF Fiber for a Flow Sensor

Inspired by seal vibrissa, an ingenious bionic flow sensor, that had four electrodes and dual-sensing circuits, was designed and fabricated using polyvinylidene fluoride (PVDF) and optical fiber. Based on the piezoelectric equation, the sensing model of this bionic vibrissa sensor (BVS) was deduced. The BVS was thoroughly investigated for airflow and oscillatory water flow monitoring applications. The results indicated that the BVS had a faster response to airflow compared with the anemometer, and it could sense the direction and the magnitude of the airflow simultaneously. The BVS could recognize the frequencies, phases, and waveforms of the oscillatory water flow. The unique dual-sensing circuit and flexible characteristics endowed the BVS with excellent underwater sensing abilities. It exhibited a very low-velocity detection threshold (0.15 mm/s). It could accurately sense the flow speed and direction at the same time by measuring only once. The success of this study paves the way for extending this technology to many applications, such as underwater detection, water leak monitoring, and blood/urine flow monitoring.