3D printing of sacrificial thermosetting mold for building near-infrared irradiation induced self-healable 3D smart structures

Digital light processing (DLP) 3D printing based 3D smart structures provide new solution for intelligent device production, but the material categories are limited to photoactive resins. Nanoparticles can endow materials with functionalities while high content or UV light absorbable ones are not compatible with DLP 3D printing. Herein, a bifunctional acrylate monomer TBMMA with hydrolysable acetal groups is synthesized and used as cross-linker for 4-acryloylmorpholine (ACMO) to build sacrificial thermosetting mold via DLP 3D printing. The addition of TBMMA simultaneously improves the printing precision and dimensional stability at higher temperature. The 3D printed mold can be hydrolyzed in mild acetic acid solution condition. The self-healable 3D smart structures is obtained by casting epoxy/carbon nanotubes composite (EPSS/CNTs) with dynamic disulfide bonds and sacrificing the 3D printed mold. Stepwise site-directed shape memory and self-healing processes of 3D smart composite triggered by near-infrared light is present. This study provided a unique strategy to adopt DLP 3D printing in fabrication of 3D smart composites with both precise structures and muti-fuctionalities, which will greatly expand the application fields of 3D smart structures in cutting-edge fields.