High Colloidal Stable Carbon Dots Armored Liquid Metal Nano-Droplets for Versatile 3D/4D Printing Through Digital Light Processing (DLP)

Liquid metal (LM) and liquid metal alloys (LMs) possess unique physicochemical features, which have become emerging and functionalized materials that are attractive applicants in various fields. Herein, uniform LM nanodroplets armored by carbon dots (LMD@CDs) were prepared and exhibited high colloidal stability in various solvents, as well as water. After optimization, LMD@CDs can be applied as functional additives for the 3D/4D printing of hydrogel and cross-linked resin through digital light processing (DLP). The light absorption of LMD@CDs not only improved the printing accuracy, but also led to the cross-linking density differential during the post-curing process. Base on the cross-linking density differential of soft hydrogel and photothermal performance of the LM, the 3D printed objects can exhibit stimulus responses to both water and laser irradiation. Additionally, the CDs shell and LM core of LMD@CDs provide the printed objects interesting photoluminescence and electric conductivity capabilities, respectively. We deduce this versatile 3D/4D printing system would provide a new platform for the preparation of multi-functional and stimuli-responsive advance materials.