A team of Lawrence Livermore National Laboratory researchers has demonstrated the 3D printing of shape-shifting structures that can fold or unfold to reshape themselves when exposed to heat or electricity. The micro-architected structures were fabricated from a conductive, environmentally responsive polymer ink developed at the Lab.
In an article published recently by the journal Scientific Reports, Lab scientists and engineers revealed a strategy for creating boxes, spirals and spheres from shape memory polymers (SMPs), bio-based “smart” materials that exhibit shape-changes when resistively heated or when exposed to the appropriate temperature.
In the paper, the researchers describe creating primary shapes from an ink made from soybean oil, additional co-polymers and carbon nanofibers, and “programming” them into a temporary shape at an engineered temperature, determined by chemical composition. Then the shape-morphing effect was induced by ambient heat or by heating the material with an electrical current, which reverts the part’s temporary shape back to its original shape.