With the advent of various metamaterials that react to stimuli, 3D printing has entered the 4D era. Intricate materials like these have a lot potential depending on how they react to their environments. One of the most popular means is using heat to induce shape and today’s story showcases this in a unique way. Morgan Barnes and Rafael Verduzco of Rice University have developed a technique that allows for the printing of liquid crystal elastomers that can deform and return to their original shape in response to temperature changes and possibly other stimuli.
The researchers developed the material using UV-curing and complex polymer networks. They state that current LCE synthesis techniques lack a simple method to program new and arbitrary shape changes. This research set out to directly program complex, reversible, non-planar shape changes in nematic LCEs. The materials have the ability to rearrange themselves in much the same way LCD screens can. Aside from heating, they can potentially also change shape in response to electric fields or UV light.
The material could have a variety of uses in soft robotics and biomedical technology. One of the most exciting prospects is how it could shape the field of robotic or artificial muscle tissue creation. It could also serve as a great way to produce microfluidics or medical devices that appropriately react to the body’s environment.
3D Printing Reversible Shapes
Creating the elastomer materials has 2 distinct steps. Firstly, the researchers used three polymers and combined them in a solvent to produce the liquid crystal elastomers. Then, the LCE requires mechanical sculpting to form a proper shape and to undergo UV-curing.
Much like a reverse of DLP, the UV light causes the liquid crystal elastomers to lose their 3D structure. However, upon cooling, they remember their original shape and the 3D structure reforms. The heat then allows it to transition between programmable complex and flat shapes.
The process, while in its infancy, showcases the ability to retain very intricate forms. It can also return to the programmed shape from an intense change in form and heat in comparison to previous metamaterials. The researchers state: “By optimizing the crosslink densities of the first and second network we can mechanically program non-planar shapes with strains between 4 – 100%.”
Featured video courtesy of chemistryworld, retrieved via their website.