Tune-able stiffness material could allow low-cost robots to switch between rigid and soft states.
To create the variably rigid material, the researchers coated a foam lattice in wax, which transforms from hard outer shell to a pliable surface with moderate heating via a wire along each coated foam strut. Turning off the current allows the wax to cool and return to a rigid state. In addition, heating the wax also the material to repair itself.
To study the material, the researchers 3D printed a foam lattice structure, to allow them to carefully control the position of each of the struts and pores.
Hosoi is now investigating the use of other unconventional materials for robotics, such as magnetorheological and electrorheological fluids. These materials consist of a liquid with particles suspended inside, and can be made to switch from a soft to a rigid state with the application of a magnetic or electric field.