Piezoelectret Sensors from Direct 3D-Printing onto Bulk Films

• DOI: 10.1109/sensors56945.2023.10324862
• Publication Date: 2023-11-28T19:02:53Z
• Authors: Youssef Sellami; Omar Ben Dali; Romol Chadda; Sergey Zhukov; Mahdi Guermazi; Alexander A. Altmann; Heinz von Seggern; Bastian Latsch; Niklas Schäfer; Mario Kupnik
• Keywords: 02 engineering and technology; 0210 nano-technology

The development of piezoelectric sensors using ferroelectrets is a very active field that is increasingly gaining importance. Recently, 3D-printing ferroelectret sensors using fused deposition modeling technique has been extensively investigated due to its unparalleled advantages in terms of design flexibility and cost-effectiveness. Nevertheless, printed structures are more rigid than bulk materials due to the minimal printable thicknesses. In this work, we present a new method that combines the advantages of 3D-printing with the high performance of bulk materials by bonding both layers in the printing process. Hereby, a polylactic acid (PLA) filament is directly printed on a 20 μm-thick bulk PLA film to form well-defined structures. This structure is thermally bonded with another PLA bulk film to form the ferroelectret. In order to enhance the sensitivity of the ferroelectrets, an additional elastomeric layer is utilized. By varying the material and thickness of the elastomeric cover, piezoelectric d₃₃-coefficients of 713 pC N ⁻¹ and 229 pC N ⁻¹ are achieved using Ecoflex™ and foamed thermoplastic polyurethane (TPU), respectively. Increasing the thickness of the Ecoflex™ cover shows a significant increase of 259 % of the piezoelectric d₃₃-coefficient.