The new process prints 3D glass microstructures through rapid curing at low temperatures

Using ultraviolet light instead of extremely high temperatures, a team of Georgia Tech researchers has developed a new approach to 3D printing tiny glass lenses and other structures for medical devices and research applications.

Their process reduces the heat required to convert the imprinted polymer resin to silica glass from 1,100°C to about 220°C and cuts curing time from 12 hours or more to just five hours. They have used it to create all kinds of glass microstructures, including lenses as small as a human hair that can be used for medical imaging inside the body.

George W. Woodruff School of Mechanical Engineering Professor H. Led by Jerry Cui, the team described their approach in the journal Scientific advances.

„Since silica is a type of ceramic, this is one of the research examples showing that it is possible to make ceramics under mild conditions,” Cui said. „This is a very challenging problem. We have a team of people from chemistry and materials science who are taking a data-driven approach to push the boundaries.

Along with the miniaturization of lenses for medical endoscopes, these 3D printed glass structures can create microfluidic devices—typically small computer chip-like devices with nano or microscale channels used to study cells or biofluids in motion. The researchers said the glass chips would offer advantages over current chips made of polymer materials, resisting corrosion from chemicals or bodily fluids.

According to Mingshe Li, first author of the study, the low-temperature process will enable the fabrication of microelectronics with glass structures.

„We can print directly on microelectronics in situ,” said Li, a postdoctoral researcher in Qi’s lab. „Semiconductor materials used in microelectronics do not withstand very high temperatures. If we want to print directly on a board, we need to do it at lower temperatures, and 200°C can definitely do the job.”

The group’s printing process offers a climate-friendly option for silica glass production.

Conventional additive manufacturing processes for glass require polymer mixtures that must be burned with heat once the desired shapes have been formed. The Georgia Tech team’s approach uses photoresin that is converted to glass using ultraviolet light, known as deep UV light. This allows for lower temperatures that save significant thermal energy. And because they don’t have to add additional polymer materials, fewer resources are involved in the first place.

The researchers used a light-sensitive resin based on a widely used soft polymer called PDMS, and they didn’t have to add silica nanoparticles to their composition like other 3D printing methods. The result is a highly transparent glass without the optical problems that can arise with added nanoparticles. The glass lenses they produced were as smooth as commercially produced silica glass.