High-biobased polymerizable deep eutectic solvents for sustainable DLP printing: assembly welding and reprintable printing

Photo-curing three-dimensional (3D) printing technology is widely used in various advanced fields. However, the extensive use of nonrenewable fossil resources as raw materials to prepare prepolymers and the disposal of 3D printing materials have imposed a serious burden on the environment. In this study, a series of bio-based, reprocessable, and reprintable digital light processing (DLP) printing polymerizable deep eutectic solvents (PDESs), named CDAG, were prepared from citric acid (CA) and glycerol (Gly), thereby offering a novel sustainable DLP printing strategy. These materials exhibited high bio-based content (46.9%-58.3%), exceptional transparency, and tunable mechanical properties They also demonstrated self-healing capabilities in certain organic solvent environments. Remarkably, hydrogen bond self-assembly conferred the printed material with reprocessability and reprintability. Multi-color objects were easily fabricated using the novel CDAG-based assembly welding printing method. This approach overcame the limitation of color distribution in traditional DLP printing. Notably, the printed models and auxiliary printing materials could be rapidly recycled and reused to print new models. Reprintable sacrificial molds, which could be easily and quickly demolded by using water, were printed. A reprintable temperature-locked quick response (QR) code was also printed using CDAG composites with thermochromic microcapsules. Furthermore, the thermochromic microcapsules could be recycled without damage and used for reprinting new QR codes. This study has important implications for developing sustainable DLP printing and green DLP manufacturing technologies. A series of high bio-based, reprocessable, and reprintable Polymerizable deep eutectic solvents (PDES), named CDAG, based on citric acid (CA) and glycerol (Gly), has been developed for sustainable 3D printing.