Piezoelectric co-axial filaments produced by co-extrusion of poly(vinylidene fluoride) and electrically conductive inner and outer layers

Abstract

The development of new thermoplastic polymer-based piezoelectric sensors with filament geometry is described. These filaments are appropriate for integration into textiles and provide new possibilities in the design and development of low cost flexible sensors produced at high rates. The developed three-layered piezoelectric monofilaments have been produced by co-extrusion using poly(vinylidene fluoride) and two different polypropylene-based electrically conductive polymers. Filaments with about 800 µm diameter, producing electrical signals proportional to the mechanical deformation applied, were obtained. The signal output has been found adequate for straightforward use with conventional piezoelectric signal conditioning systems. One of the conductive polymers tested allowed better filament geometry and process stability. This paper describes the co-extrusion production process and the results obtained in the electromechanical tests performed.