Stretchable alternating current electroluminescent fiber based on transparent and highly conductive dual-network imidazolium chloride ion–gel electrodes for wearable display applications

Abstract

Wearable displays are an ultimate form of signal sensing for individual safety and health, but the traditional displays used are typically flat and have complex electronics, leading to a lack of ease and comfort in wearing them. Fibrous alternating current electroluminescent (ACEL) devices are effective solutions in this regard. Herein, a low-cost, low-power, stretchable ACEL fiber was prepared, wherein an ionogel was selected as the electrode, ZnS:Cu powder as the luminescent powder, and epoxy resin slurry as the substrate of the electroluminescent layer. It was found that the 1-ethyl-3-methylimidazole chloride (EmimCl), which has good compatibility with the gel skeleton, could improve the mobility and ionic conductivity of the polymer chains in the sodium alginate (SA) and polyacrylamide (PAM) ionic–covalent double-network (DN) hydrogel system. When the content of EmimCl in the gel fiber was 100 wt%, the ionic conductivity of the gel was 2.93 S m⁻¹, the elongation at break was 580%, and the light transmittance was 88%. In addition, a braided structure consisting of stretchable ACEL fibers and gel fibers was designed. The intersection of the stretchable ACEL fibers and gel fibers could produce electroluminescent pixels that could form an arbitrary controllable pattern display. The display contained a variety of letters, an intuitive graphic design, and a combination of automatic and manual control modes selected through a miniature light-sensitive control system. Flexible fiber devices could be designed and integrated into textiles to meet the unique requirements of a variety of flexible and wearable display technologies.