Chemists’ New Process Offers Safer 3D Printing Option, Requiring Less Energy and Cost

Vat photopolymerization, a powerful type of 3D printing driven by light, has led to big advances in plastics manufacturing, but it uses ultraviolet (UV) light, which is energy-intensive, costly and potentially damaging to living cells. Now chemistry researchers at The University of Texas at Austin have developed a new process that has the potential to revolutionize light-driven 3D printing by using visible light instead of ultraviolet light. The new process allows for highly precise, rapid and inexpensive 3D-printed materials, and it holds potential for a wide range of applications, including in dentistry and medicine.

The process is outlined in a paper published yesterday in the journal ACS Central Science. 

“Light-driven 3D printing, or photopolymerization, is faster and much more precise than many other additive manufacturing approaches, like the filament-style printing that often comes to mind for hobbyists,” said Zak Page, assistant professor of chemistry and a corresponding author on the paper. “This new process further improves the precision of light-driven 3D printing, while making it more accessible and efficient, opening a lot of possibilities.”

The research team’s breakthrough was enabled by a chemical process called triplet fusion. This process uses unique chemical structures that can convert low energy, long wavelength light, such as green light, into shorter, higher energy wavelengths of light, such as violet light. Page and colleagues previously created a process that directly used low energy visible light without triplet fusion for 3D printing. However, the new triplet fusion process operates by a mechanism that will improve the spatial precision of printed structures, while simultaneously showing enhanced resin stability that will facilitate commercialization.

Researchers believe the new process could be harnessed for engineering materials for medicine, robotics and electronics where interfacing with delicate human tissues is necessary, improving things such as joint replacements, prosthetics and implants. 

“This also expands the kind of composites that we can create,” said Sean Roberts, associate professor of chemistry and co-corresponding author on the paper. “Currently, composites are limited in 3D printing because they can easily scatter UV light. Longer wavelengths of light are less easily scattered and can often penetrate deeper into materials. This allows for a more flexible printing process, and we can create things that are stronger, more flexible or more resistant.”

Connor J. O’Dea, Jussi Isokuortii and Emma E. Comer of UT were also authors on the paper. The research was funded by the National Science Foundation, the Robert A. Welch Foundation and the Research Corporation for Science Advancement.