Additive manufacturing processes enable fabrication of complex and functional three-dimensional (3D) objects ranging from engine parts to artificial organs. Photopolymerization, which is the most versatile technology enabling such processes through 3D printing, utilizes photoinitiators that break into radicals upon light absorption. We report on a new family of photoinitiators for 3D printing based on hybrid semiconductor-metal nanoparticles. Unlike conventional photoinitiators that are consumed upon irradiation, these particles form radicals through a photocatalytic process. Light absorption by the semiconductor nanorod is followed by charge separation and electron transfer to the metal tip, enabling redox reactions to form radicals in aerobic conditions. In particular, we demonstrate their use in 3D printing in water, where they simultaneously form hydroxyl radicals for the polymerization and consume dissolved oxygen that is a known inhibitor. We also demonstrate their potential for two-photon polymerization due to their giant two-photon absorption cross section.
Bibliographical noteFunding Information:
This work was financially supported in part by the Israel Science Foundation (U.B., Grant 1560/13) and in part by the National Research Foundation of Singapore under the CREATE program (S.M.). We acknowledge E. Blayvas of the unit for nanocharacterization for assistance in the environmental scanning electron microscopy imaging performed at The Hebrew University Center for Nanoscience and Nanotechnology Edmond J. Safra Campus, Jerusalem, Israel.
© 2017 American Chemical Society.
- 3D printing
- Semiconductor-metal hybrid nanoparticles