Optimization of Fully Screen‐Printed Electrostrictive Multilayer Actuators

ABSTRACT

Electroactive polymers (EAP) are commonly used as actuating materials in soft robotic systems. Among EAPs, the relaxor ferroelectric poly(vinylidene fluoride‐ ter ‐trifluoroethylene‐ ter ‐chlorotrifluoroethylene) (P(VDF‐ ter ‐TrFE‐ ter ‐CTFE)) stands out for its large reversible strain (4%–5 %), however requiring high voltage for actuation. To limit the applied voltage, a fully screen‐printed multilayer architecture consisting of alternating thin electrostrictive layers (5 µm) and PEDOT:PSS electrodes on a flexible substrate is proposed. The electroactive ink consists in a (P(VDF‐ ter ‐TrFE‐ ter ‐CTFE)) terpolymer with 4.7 mol% of CTFE selected for its higher crystallinity compared to the frequently used 8 mol% CTFE composition. In this study, a multi‐parametric design (aspect ratio, surface of actuation, thickness of the EAP layer, thickness of the substrate) optimization to enhance actuator performance is presented. The results reveal that increasing the aspect ratio leads to a larger bending angle but a lower blocking force, whereas increasing the surface of actuation increases both the bending angle and the blocking force. Additionally, the guidelines for successful screen‐printing of reliable multilayer actuators are presented. These findings underline the potential of multilayered electrostrictive actuators for soft robotics.