Ultra‐High Bending Angle of Miniaturized Piezoelectric Actuator Screen‐Printed on Stiff Substrate

Abstract

The miniaturization of bending actuators is valuable for robotics, embedded systems, and medical applications, but often results in performance loss. This study presents a multilayered, screen‐printed PVDF‐TrFE (polyvinyledenedifluoride‐trifluoroethylene) actuator less than one millimeter wide, designed to achieve large bending angles. To achieve this, the various causes of performance loss are first identified through a cross‐sectional study: all influencing parameters are studied, from geometry to morphology. The geometrical profile of the layers, their design, dielectric and ferroelectric characteristics, as well as the orientation of the β ‐phase of PVDF‐TrFE responsible for the displacement are all measured. These results, coupled with the development of an analytical model, have enabled the identification of an optimized architecture as well as a new substrate capable of attaining large angles. Compared with conventional metal–insulator–metal capacitor structures, the optimized actuator features reduced margins to maximize the bending angle. Furthermore, the actuator is screen‐printed on a new type of stiff substrate (i.e., nickel, rarely used in printed electronics), which not only improves performance by 70% compared to the polyimide often used but also offers interesting features such as radio‐opacity, which is much sought‐after in the medical field.