4D 프린팅

https://phys.org/news/2020-06-lab-d.html

Lab makes 4-D printing more practical

Soft robots and biomedical implants that reconfigure themselves upon demand are closer to reality with a new way to print shapeshifting materials.

Researchers developed a method to print objects that can be manipulated to take on alternate forms when exposed to changes in temperature, electric current or stress.

They first reported their ability to make morphing structures in a mold in 2018. But using the same chemistry for 3-D printing limited structures to shapes that sat in the same plane. That meant no bumps or other complex curvatures could be programmed as the alternate shape.

"We needed a method to control and define this shape change. Our simple idea was to use multiple reactions in sequence to print the material and then dictate how it would change shape. Rather than trying to do this all in one step, our approach gives more flexibility in controlling the initial and final shapes and also allows us to print complex structures."

The lab's challenge was to create a liquid crystal polymer "ink" that incorporates mutually exclusive sets of chemical links between molecules. One establishes the original printed shape, and the other can be set by physically manipulating the printed-and-dried material. Curing the alternate form under ultraviolet light locks in those links.

 

reference

Morgan Barnes et al, Reactive 3D Printing of Shape Programmable Liquid Crystal Elastomer Actuators, ACS Applied Materials & Interfaces (2020). DOI: 10.1021/acsami.0c07331