David Moore, Lorenzo Barbera, and Kunal Masania in the Complex Materials group led by ETH processor André Studart have developed a special resin that contains a plastic, and organic molecules to which glass precursors are bonded.

The resin can be processed using commercially available Digital Light Processing technology. This involves irradiating the resin with UV light patterns. Wherever the light strikes the resin, it hardens because the light sensitive components of the polymer resin cross link at the exposed points. The plastic monomers combine to form a labyrinth-like structure, creating the polymer. The ceramic-bearing molecules fill the interstices of this labyrinth.

An object can thus be built up layer by layer. The researchers can change various parameters in each layer, including pore size: weak light intensity results in large pores; intense illumination produces small pores. “We discovered that by accident, but we can use this to directly influence the pore size of the printed object,” says Masania.

The researchers are also able to modify the microstructure, layer by layer, by mixing silica with borate or phosphate and adding it to the resin. Complex objects can be made from different types of glass, or even combined in the same object using the technique.

I'm always interested in the ways that 3D printing technology can be used to create otherwise unobtainable science fictional materials. One of my favorite descriptions of an entire city made of glass by an alien race can be found in The Godmakers, a 1972 novel by Frank Herbert:

“Your city—I saw very tall buildings. Of what do you build them?”

“In your tongue, glass,” Tanub said. “The engineers of the Delphinus said it was impossible. As you saw, they are wrong.”

Stetson’s voice came hissing on the carrier wave: “A glass-blowing culture! That’d explain a lot of things.”

A glowing of many lights grew visible through the giant tree trunks. It brightened as the sled crept through the jungle’s edge and emerged in cleared land looking across about two kilometers of open space at the city.

Orne stared upward in awe. The Gienahn city fluted and spiraled into the moonlit sky, taller than the tallest trees. It appeared a fragile lacery of bridges, glowing columns and winking dots of light. The bridges wove back and forth from column to column until the entire visible network seemed one gigantic dew-glittering web.

“All that with glass,” Orne murmured.