High dispersibility Organosilicon@ZnO-NPs prepared by spray sedimentation method: Similar chain extender enhances the strength, antimicrobial, and UV shielding of 3D printing composite materials

Additive manufacturing is advancing rapidly and gaining widespread adoption across various industries. Although ZnO nanoparticles (ZnO-NPs) hold significant promise, their tendency to agglomerate in photosensitive resins presents a challenge, obstructing the UV-curing process in 3D printing. In response to this, we have innovatively developed a PUA-based functional photosensitive resin for 3D printing, which incorporates highly dispersible Organosilicon@ZnO-NPs. These nanoparticles exhibit smaller sizes and a more uniform distribution, achieved through the spray sedimentation method. Using Digital Light Processing (DLP), the resin demonstrated enhanced mechanical properties, including a tensile strength of 75.188 MPa (a 96.34 % improvement), a flexural modulus of 2223.276 MPa (a 71.81 % improvement), as well as high-precision 3D-printed material. The material also exhibited efficient broad-spectrum antimicrobial properties (99.64 % against E. coli and 98.93 % against S. aureus ) and strong UV-shielding performance (97.32 % UV-blocking rate). Mechanistically, the improvement in mechanical properties is attributed to the role of Organosilicon@ZnO-NPs, which function similarly to an amine chain extender. This allows them to establish a robust hydrogen bonding network within the PUA-based photosensitive resin and react with free –NCO groups in the system. The antimicrobial and UV-shielding effects stem from the combined actions of Organosilicon@ZnO-NPs, which disrupt bacterial cell membranes, release Zn 2 ⁺ ions, and scatter and absorb UV light. This study paves the way for novel applications of ZnO-NPs in UV-curing 3D printing, opening new avenues for innovation.