Direct ink writing of coaxial electrostatic fibers with customizable cross-sections and functional properties

Abstract

Electrostatic devices have attracted significant interest in recently years, with wide applications in areas such as actuators, sensors, adhesive devices, etc. The common fabrication method of electrostatic devices is through layer-by-layer stacking. However, this process is time-consuming and restricts both design flexibility and performance, presenting a substantial challenge for the rapid development of complex electrostatic systems. To address this problem, we report a method for fabricating coaxial electrostatic fibers (CEFs) using direct ink writing (DIW) method. Silicone-based inks with high conductivity and a high dielectric constant were developed, with their rheological properties optimized for smooth, precise printing. Using these customized inks, electrostatic fiber structures with varying geometries, including one-dimensional fibers, two-dimensional meshes and layered structures, as well as three-dimensional coils and meshes, were successfully manufactured. By modifying the nozzle shape and adjusting the flow rate multiplier, diverse fiber cross-sections and diameters were achieved. The coaxial printing of fiber, layered clutch, and shape morphing devices demonstrated that utilizing highly-dielectric inks and customized cross-sectional geometries significantly improved the device performance. This technique marks a significant advancement in the rapid and efficient fabrication of electrostatic devices, expanding their potential applications in actuators, robotics, haptic interfaces, etc.