Photo-assisted ultrasonic curing for ultrafast and deep prototyping based on coumarin derivatives.

• Coum-Ph-OC 12 H 25 possesses strong visible-light absorption and photobleaching ability. • The dual curing behavior could be activated by both visible light and ultrasound. • An excellent curing depth of 15 cm was achieved by this novel curing strategy. • The models (V≈30 cm3) could be completely cured within 30 min by this strategy. Although photocuring is currently the most commonly used method in 3D additive manufacturing, it still faces significant challenges in rapid prototyping of thick materials due to the limited penetration of light. Ultrasonic technology has the advantages of high penetration depth and unparalleled cavitation, offering opportunities for enabling additive manufacturing of thick materials. In this study, a coumarin-based two-component system composed of Coum-Ph-OC 12 H 25 and N-phenylglycine as initiator and hydrogen supplier, respectively, was developed to achieve ultrasonic curing of tripropylene glycol diacrylate (TPGDA). The ideal curing efficiency of this two-component system was optimized to 90 %, and ultrasonic curing of thick materials was achieved with a penetration depth of up to 15 cm. Moreover, electron spin resonance (ESR) spectroscopic measurements demonstrated the free-radical reaction mechanism. It is believed that this research has the potential to expand the 3D additive manufacturing technology and pave the way for future developments in this field. [ABSTRACT FROM AUTHOR]