Fabrication and Characterization of Electroactive Polymer Actuators for High-Resolution Adjustable X-ray Optics

This study investigates adjustable X-ray mirror technologies using electroactive polymer films a s a ctuators to correct figure deformations in sub-millimeter-thick X-ray mirror s hells. Such deformations can arise from fabrication errors, stray mounting loads, coating stresses, or mounting processes, adversely affecting the optic’s angular resolution. Our research focuses on the fabrication, testing, and application of individually-addressable actuator cells made from micrometer-thick electroactive polymer (PVDF-TrFE) films on flat silicon wa fers. Electroactive polymers are capable of generating significant strains at low voltages, and offer promise for correcting deformations in sub-millimeter-thick mirror shells. Our approach demonstrates a scalable, low-cost, and low-temperature method for actuator fabrication. We selected PVDF-TrFE as the actuator material due to its excellent piezoelectric properties and its proven suitability for space environments. The fabrication of polymer films is cost-effective and scalable, making them suitable for industrial applications. Additionally, their low processing temperature (below 140ºC) minimizes thermally induced imperfections in the substrate. In this paper, we will present measurements that track figure changes and integrated stress associated with our fabrication protocol. Using interferometry setup at the University of Iowa, we measured figures of the wafers before and after actuator fabrication. Figure changes were dominated by the quadratic Zernike term. We will also present two different geometric implementations of our actuator arrays.