Strain characteristics of additive manufactured polyvinylidene fluoride (PVDF) actuators

Polyvinyldene fluoride (PVDF) polymer piezoelectric actuators were manufactured using an electric poling-assisted additive manufacturing (EPAM) process and tested for actuation strain in the thickness direction. A heterodyne interferometer was used to measure the strain developed by the actuators as a function of applied voltage. Results were compared to a commercially available ceramic lead-zirconium-titanate (PZT) actuator. The EPAM PVDF samples exhibit strains up to 8.78 mϵ, compared to 1.7 mϵ developed by PZT samples at their maximum working voltages in linear ramp testing (860 V for EPAM PVDF and 200 V for PZT). The response of the EPAM PVDF samples to an applied force was tested to measure the piezoelectric effect, although no actual piezoelectric constants are calculated with this method. Results show that strain measurements of EPAM PVDF samples were up to 5.2 times greater than comparable measurements of PZT samples. However, the degree of piezoelectricity between EPAM PVDF samples varies so quality control is required for the EPAM process to ensure sample performance.