MIT and SUTD use light to 3D print memory-materials

The polymer mix used by the team is rigid at room temperature, but rubbery and pliable when heated above a certain point (40-180 degrees Celsius). This means it can be printed in a particular shape, ‘frozen’ in a different shape at room temperature, then reactivated into the printed shape through heating. Potential applications include actuators for solar panels, and drug delivery devices that open when infection is detected.

“We ultimately want to use body temperature as a trigger,” said Nicholas X Fang, associate professor of mechanical engineering at MIT. “If we can design these polymers properly, we may be able to form a drug delivery device that will only release medicine at the sign of a fever.”

Conventional 3D printing is commonly used to make custom designs of memory materials. However, this technique only allows the user to create designs with details no finer than a few millimetres. For the more intricate designs that they required, the MIT and SUTD team pioneered a new method called microstereolithography, where they used light from a projector to print patterns on successive layers of resin.