A new 3D-printed material with shape-shifting capabilities has been invented by researchers from MIT, Max Planck Institute and Stony Brook University.
The material is a mix of polyurethane wax and foam, and was developed by MIT Professor of mechanical engineering and applied mathematics, Anette Hosoi, and her former graduate student Nadia Cheng, along with other researchers.
The Defense Advanced Research Projects Agency (DARPA), as part of the Chemical Robots program, wanted to create a “squishy” deformable robot capable of squeezing through tight spaces and then expanding again to move around a given area, Hosoi said.
Building a deformable robot necessitated developing a material that could switch between a soft and hard state, because very soft structures are hard to control, and their movements difficult to predict.
This was achieved by coating a foam structure in wax. The researchers chose foam because it can be squeezed into a small fraction of its normal size, but once released will bounce back to its original shape. A wax coating can change from a hard outer shell to a soft, pliable surface with moderate heating.
Heating was done by running a wire along each of the coated foam struts and then applying a current to heat up and melt the surrounding wax. Turning off the current again would allow the material to cool down and return to its rigid state.
In addition to switching the material to its soft state, heating the wax in this way would also repair any damage sustained, Hosoi said.
The material can be used to build deformable surgical robots which have the ability to move through the body to reach a particular point without damaging organs or vessels along the way.
The material can also be used to build robots for use in search-and-rescue operations, to squeeze through rubble looking for survivors.
The researchers worked with robotics company Boston Dynamics in developing the material.