MIT’s milliMorph Platform Brings Actuation for Millimeter-Scale Shape-Changing Materials

Researchers from MIT’s Tangible Media Lab have developed a design and fabrication system for building fluidic channels and chambers on a millimeter-scale for the actuation of thin-film shape-changing materials. To that end, the team's milliMorph platform is a 4D design space for creating those millifluidic systems that offer a heat-sealing fabrication process, and academic demonstrations of those fabricated materials for haptics, ambient devices, and soft robotics applications.

Fluidic-based shape-changing materials are gaining interest in the soft robotics industry. The ability to bend appendages and adapt to the environment quickly and efficiently gives soft robots the edge over rigid platforms in various applications, including the ability to navigate in tightly confined spaces. Designing those soft robots is easier said than done, but the team's new approach would make it a bit easier to accomplish, even for other platforms such as wearables and human-computer interfaces.

As mentioned earlier, the milliMorph is a 4D platform that features a four-part design process, with the first being thin-film materials selection, such as Mylar or PET, which can be actuated and returned to their original shape without being damaged. The next phase is the actuation medium, which has four possibilities — air, water, low boiling point liquid, and UV sensitive resin. Air allows actuation at very high frequencies, while water is more suitable for sequence control and stiffness. Low boiling point liquid, for example, is best for untethered mobile applications, and resin best suited for 2D/3D applications.

After materials are selected, it’s on to the embedded sensing phase, where the circuitry is added to the design. For demonstration purposes, the scientists chose a metalized aluminum-coated Mylar film, which they then etched different circuit (sensing/heating) designs. Upon completion, it’s on the actuation method phase, where designs can use an electric or non-electric application. For example, some designs could use an airbag that’s squeezed to generate the desired shape, while others might require a compressor.

Once finalized, designs are then transferred over to the fabrication process, which starts by adding a CAD model of the desired non-composite design to a PC, which is then fabricated with the internal millifluidic chambers and channels using a NoHAS (Non-contact Hot Air Sealing) CNC heat-sealing platform. The machine seals the film in the desired pattern without ever touching the material, ensuring the device functions and actuates in the desired manner.

The researchers demonstrated the milliMorph platform by creating a mini butterfly robot that beats its wings at 10MHz, a haptic latex glove that provides a texture change when touching different objects, and a shape-changing sticker that responds to temperature changes. It will be interesting to see what new devices can be fabricated using the platform in the near future.