From the ACS Press Room

Modern origami method creates glass shapes by folding

INDIANAPOLIS, March 28, 2023 The ancient art of origami is well known for transforming sheets of paper and other foldable materials into complex 3D shapes. But now, chemical engineers have extended the centuries-old practice to produce intricate shapes made of glass or other hard materials. Their thoroughly modern method, which can be combined with 3D printing, could have applications ranging from sculpture to catalysis and beyond.

says Tao Xie, Ph.D., the project’s principal investigator.

Typically, glass and ceramics are shaped in a mold or are 3D printed in the desired final structure. But a mold can’t produce a complicated shape, Xie says. And although 3D printing can do so, it’s slow, and an object can be flimsy and need extra support while it’s being made. In addition, the printed item usually has a layered texture that might not be the ideal appearance. The team set out to see if they could overcome these shortcomings.

Yang Xu, a graduate student who works in Xie’s lab at Zhejiang University, devised a technique in which she mixed nanoparticles of silica the main ingredient for making glass into a liquid containing several compounds. Curing the mixture with ultraviolet light produced a cross-linked polycaprolactone polymer with tiny beads of silica suspended in it, like raisins in raisin bread.

The researchers will present their results today at the spring meeting of the American Chemical Society (ACS). ACS Spring 2023 is a hybrid meeting being held virtually and in-person March 26–30, and features more than 10,000 presentations on a wide range of science topics.

In earlier work, the researchers used origami and the related technique of kirigami which combines cutting with folding to shape soft materials made of polymers. “But we wanted to extend these techniques to glass and ceramics, which are much harder to process into complex shapes than polymers,”

Next, Xu cut, folded, twisted and pulled on sheets of this translucent polymer composite, which has mechanical properties similar to paper, to make a crane, a feather, a lacy vase and a sphere made of intertwined ribbons, among other objects. If she did this at room temperature, the composite retained its new shape fairly well throughout the remaining production steps. Xu discovered that’s because the folding and stretching process irreversibly disrupts the interface between some of the silica particles and the polymer matrix. But if it’s critical to fully retain the new