Preparation and properties of metal-core piezoelectric fibers for dynamic sensing using the double heat-shrinkage method.

Metal-core piezoelectric fibers (MPF)are coaxial fibers composed of a metal core, piezoelectric material, conductive material, and insulating material. They possess piezoelectric effects and hold great application potential in sensors and intelligent products. The most commonly used preparation method for metal-core piezoelectric fibers is electrospinning. However, this method is extremely sensitive to process parameters. It demands high voltage control, and it is difficult to precisely adjust the solution concentration and viscosity. This makes it challenging to manufacture piezoelectric fibers with global dynamic sensing capabilities, resulting in unstable product quality, such as uneven fiber diameters and internal structural defects, which restricts the application of metal-core piezoelectric fibers. In this research, metal-core piezoelectric fibers were prepared via a double heat-shrinkage thermoplastic approach, employing single thermoplastic piezoelectric polyvinylidene fluoride (PVDF) tubes and thermoplastic insulating silicone tubes. This study constructed a testing platform for metal-core piezoelectric fibers to explore their piezoelectric, impact, vibration, and durability attributes. The stability and consistency of the piezoelectric properties throughout the entire domain were also evaluated. The experimental outcomes demonstrate that the metal-core piezoelectric fibers fabricated herein not only possess a straightforward manufacturing process and low equipment cost but also display high manufacturing efficiency and excellent cross-sectional coaxiality. They exhibit remarkable response and feedback capabilities and can be applied to monitor the dynamic performance of piezoelectric fibers across the whole domain. This offers a novel concept for the large-scale and efficient production of metal-core piezoelectric fibers with stable performance.