Researchers at Northwestern University and the University of Illinois at Urbana-Champaign say they have developed a fabrication technique to create 3D micro- and nanostructures. The researchers claim the process offers advantages over 3D printing, also known as additive manufacturing.

The technique reportedly mimics the action of a children’s pop-up book, starting as a flat 2D structure and popping up into a more complex 3D structure. Using a variety of advanced materials, including silicon, the researchers say they produced more than 40 different geometric designs, including shapes resembling a peacock, flower, starburst, table, basket, tent and starfish.

Northwestern’s Yonggang Huang, one of three authors on a study published in the journal Science, says the team first fabricated a 2D structure on a stretched elastic material. They they released the tension, and “up pops a 3D structure. The 2D structure must have some place to go, so it pops up.”
The pop-up assembly technique could be useful in building biomedical devices, sensors and electronics, researchers say.

The research team claim the technique is fast and inexpensive, and can be used to build many different structures at one time; utilize many different materials, including silicon; incorporate different materials into one hybrid structure; be used to build structures on both micro- and nano-levels (down to a thickness of 100 nanometers); and produce a range of different geometries.

Complex, 3D structures form readily in biology (think of bones, neural circuits, networks of veins) but manmade devices are limited by available manufacturing methods, the team says.

In the 2D pop-up manufacturing process, everything is fabricated in two dimensions. Keys to the technique are strong points of adhesion and weak points of adhesion between the 2D structure and the elastomer it is placed on. When the stretch is released, compression buckling takes place. The strong adhesion points stay in the plane of the elastomer while the weak points break away. The intended structure pops up into three dimensions.

The U.S. Department of Energy supported the research.

IHS 3D Printing Intelligence Service

Question or comment on this article? Contact an editor: engineering360editors@ihs.com