The Polymer Society of Korea

Abstract

Flexible electroluminescent devices are essential for wearable electronics and soft robotics, but conventional fabrication methods limit design complexity and customization. Here, we demonstrate three co-printable functional inks for direct ink writing (DIW) 3D printing of stretchable EL devices. The ionic hydrogel electrodes, crosslinked with Pluronic F-127 dimethacrylate (FDMA), achieve high ionic conductivity and optical transparency while maintaining exceptional stretchability. The electroluminescent ink, based on a UV-curable silicone matrix with embedded phosphors, produces stable brightness at low driving voltages. The fully 3D-printed devices operate reliably over repeated stretch-release cycles and maintain constant brightness under mechanical deformation. This platform enables rapid prototyping of complex three-dimensional geometries for customizable wearable optoelectronics and human-machine interfaces.