New manufacturing process could lead to microscale soft robots, advanced sensors, and materials that release stored strain energy in controlled ways for shape morphing and energy absorbing applications.
How small can you make a jack-in-the-box? Thanks to mechanical engineers from the UCLA Samueli School of Engineering, 30 micrometers—about the size of three red blood cells.
The researchers have developed a process to make customized tiny mechanical parts that have strain energy, just like that jack-in-the-box, already built in. The first-of-its-kind process could lead to shape-changing materials, microscale mechanisms, sensors and, and even soft micro-robots. The research was recently published in Materials Horizons.
“The ability to spring-load mechanisms that are printed at small scales is important for creating new materials that, when impacted, can release the stored energy in controlled ways,” said Jonathan Hopkins, an assistant professor of mechanical and aerospace engineering and the principal investigator on the research. “Such materials could be used as shape-morphing or deployable structures that swell in regions that have been fractured to instantly compensate for the damage. They could also be used for precision sensors that use spring-loaded energy to mechanically amplify slight movements.”
The UCLA team, from Hopkins’ Flexible Research Group, included graduate student Samira Chizari, and postdoctoral scholar Lucas Shaw.
The team combined two optical microfabrication tools for the first time: two-photon lithography, which uses a laser to print polymer structures layer by layer, and holographic optical tweezers that hold and move tiny objects.
In addition to the jack-in-the-box, they made two other microsystems to demonstrate the process’ capabilities: a lattice with embedded strain energy, similar to a bed with springs; and a system that becomes thicker when stretched. These three mechanisms are only examples of a vast variety of microstructures that could not be made in the microscale with another process, they said.
The research was supported by the Air Force Office of Scientific Research and the Department of Energy through the Presidential Early Career Award for Scientists and Engineers. Chizari is supported by a National Science Foundation Graduate Research Fellowship.
Hopkins and members of his research group have also recently published research in Nature Communications, on a new type of lattice-like structure that can dramatically change its shape but still retain its stiffness. That work was made possible at small scales by the advances of this paper in Materials Horizons.