DLP printing of tough organogels for customized wearable sensors

Abstract

Conductive gels are highly desirable for wearable electronics and sensors. Photocurable 3D printing technology provides an efficient way for the preparation of gel-based microstructured electrodes. However, how to obtain gels with both high stretchability and 3D printability, is still one of the current challenges to customize wearable sensors through 3D printing. Herein, we constructed a photocurable composite mainly composed of N-methylol acrylamide (NAM) and ethylene glycol (EG) for the successful 3D printing of gel-based wearable sensing devices. After printing, abundant hydrogen bonds formed among the hydroxyl groups on the side chains works synergistically with the covalent bonds, enabling the gel to reach excellent mechanical properties and the elongation at break reach 730%. The as-printed gel incorporated with sodium chloride has excellent resistance signal detection ability, which can accurately and stably detect human motion. In addition, the EG endows the printed gels with excellent anti-freezing and anti-drying properties, enabling the wearable sensors to be used in harsh environments. In summary, this work introduced a facile strategy for the rapid preparation of gel-based flexible sensors with microstructure by photocurable 3D printing, which provides the possibilities for the manufacturing of artificial intelligence and smart electronics.