Researchers at ETH Zurich have developed a new memory-material based design that evolves with environmental stimuli. These 4D printed structures contain programmable actuators that deploy autonomously and change shape using temperature alterations as the catalyst. They are also load-bearing before and after actuation, and thus can serve as great construction materials.
Professor Kristina Shea and doctoral student Tian Chen were the masterminds behind this incredible study. They stored multiple shapes into a shape memory polymer and in reaction to heat it would transform into various shapes. Among them were pyramids and hyperbolic paraboloid shapes, showing off a diverse range of capabilities.
“Using a shape memory polymer as the temperature controllable energy source and a bistable mechanism as the linear actuator and force amplifier, the structures achieve precise geometric activation and quantifiable load-bearing capacity,” the study explains. “The proposed unit actuator integrates these two components and is designed to be assembled into larger deployable and shape reconfigurable structures.”
Creating 4D Construction Polymers
The researchers used multimaterial inkjet 3D printing to achieve the right configurations. The complex designs were a result of precise and selective deposition of the photoreactive liquid resins with varying glass transition temperatures and stiffness. Then they combined the polymer with a Mises truss, a bistable mechanism. Consequently, this gave them the ability to create a substance with 2 wildly different equilibrium states.
They printed the object using a Stratasys Objet3 Connex500 multimaterial 3D printer. The material consisted of FLX9895 (shape memory polymer), RGD525 (temperature-resistant rigid plastic) and Agilus30 (elastomer-like material).
The complex polymer transitions from a flat shape to an incredibly different structure. All this also comes with the ability to regulate shape and temperature smoothly. Although shape-changing polymers have long been a staple of 4D printing, they’ve never been quite this applicable. While the research is in early phases, it has so many applications in industrial causes or space flight. This is especially useful in construction or renovation where load-bearing tech is almost always needed.
The study is available here.