
An ink for 3D-printing flexible devices
Researchers are targeting the next generation of soft actuators and robots with an elastomer-based ink for 3D printing objects with locally changing mechanical properties
For engineers working on soft robotics or wearable devices, keeping things light is a constant challenge: heavier materials require more energy to move around, and – in the case of wearables or prostheses – cause discomfort. Elastomers are synthetic polymers that can be manufactured with a range of mechanical properties, from stiff to stretchy, making them a popular material for such applications. But manufacturing elastomers that can be shaped into complex 3D structures that go from rigid to rubbery has been unfeasible until now.
“Elastomers are usually cast so that their composition cannot be changed in all three dimensions over short length scales. To overcome this problem, we developed DNGEs: 3D-printable double network granular elastomers that can vary their mechanical properties to an unprecedented degree,” says Esther Amstad, head of the Soft Materials Laboratory in EPFL’s School of Engineering.
Eva Baur, a PhD student in Amstad’s lab, used DNGEs to print a prototype ‘finger’, complete with rigid ‘bones’ surrounded by flexible ‘flesh’. The finger was printed to deform in a pre-defined way, demonstrating the technology’s potential to manufacture devices that are sufficiently supple to bend and stretch, while remaining firm enough to manipulate objects.
