Influence of Build Orientation on Additively Manufactured Polyvinylidene Fluoride with Electrical Poling for Strain Sensing and Energy Harvesting Applications

Additive manufacturing (AM) of sensors has become a potential manufacturing route worldwide due to its flexibility of incorporating geometrical complexity and micro-structural engineering of materials constituting the sensors. The strain sensors fabricated using this route with flexibility and sensitivity for the precise measurement of strain with a wide range of values. In this work, the polyvinylidene fluoride (PVDF) piezoelectric material-based strain sensor was fabricated using the material extrusion process (ME). The sensing material PVDF, was extruded with three different printing flat orientations such as 0°, 45°, and 90° to understand the effect it has on strain sensing characteristics studies. The fabricated PVDF material was poled by two poling methods contact poling and corona poling process for enhancements of the β-phase in the microstructure and to get better piezoelectric properties. The mechanical test results have shown that the maximum values of Young's Modulus (131.17 ± 2.25 MPa) and Ultimate tensile strength (23.57 ± 0.76 MPa) were observed for the material fabricated with the printing orientation of 45^°. The studies on strain sensing characteristics were made for all the samples and found that the sample printed in 0^° orientation and poled with the corona poling process has shown the maximum output voltage, short circuit current and power output of 11 V, 0.9 μA and 5.5 μW under the stain condition of 20%. During mechanical testing, the sample printed with a 0° orientation yields more strain as well as the strain sensing results show that effective deformation on the 0^° orientation sample leads to providing excellent piezoelectric output. Under different stretching and bending conditions, the fabricated device could serve as both a strain sensor and a piezoelectric energy harvester as observed from the present work.