Fabrication and properties of sandwich dielectric structures with piezoelectric response

In the present study, the fabrication and properties of sandwich dielectric structures with piezoelectric response are studied. The construction of 3-layer sandwich dielectric structure, including electret and non-electret layers, exhibiting piezoelectric response is presented. The fabrication process including the 3-D printing method and the molding technique is described. The model allowing calculation of piezoelectric coefficient d₃₃ for the designed structure is proposed. The electrical properties of particular layers were examined and the assumption made in derivation of the structure model is verified. Two different charging methods were applied to activate the piezoelectric properties of the structure. The maximal calculated value of the piezoelectric coefficient d33max is found to be approximately 613 pC/N. The calculated data are compared with the experimental results. The static coefficient measured d₃₃ is found to be up to 544 pC/N. The influence of applied static pressure on piezoelectric properties was examined and power-function approximation was applied to received data. The time stability of the piezoelectric coefficient d₃₃ in long-term was also noted. The influence of particular electrical and mechanical properties on piezoelectric d₃₃ coefficient is discussed. The further research including modeling of mechanical properties of the structure is proposed.