This hands-free origami folds itself

If you find paper origami too hands-on, this technique might be for you!

In a new Science Advances study, researchers have developed a new and simple self-folding origami technique. The technique uses a PowerPoint slide and a projector to cast a grayscale pattern of light and dark shapes onto a thin layer of resin. The light causes the resin to bend and self-fold into intricate origami shapes according to the projected pattern.

We spoke with Jerry Qi of Georgia Institute of Technology about the work.

ResearchGate: What motivated this study?

Jerry Qi: Many different fields are interested in self-folding origami, for example microelectronics, soft machines, and mechanical metamaterials. Current methods to fabricate self-folding origami shapes rely on complex material systems or structure design, and always involve a relatively tedious fabrication process. We wanted to develop a self-folding method that is simple and applicable to a wide range of materials.

RG: Can you tell us what you developed?

Qi: We developed a new and simple method to make self-folding origami shapes from flat polymer sheets. With this method, we first create a grayscale pattern. Then, the pattern is projected onto a layer of liquid polymer resin with a commercial projector. After the resin is solidified and taken out, it deforms itself into a 3D origami shape.

A tiny origami structure created through a self-folding process is shown on a quarter for size comparison. Credit: Rob Felt, Georgia Tech.

RG: How does this work?

Qi: When a layer of liquid resin with photoabsorbers is exposed to light irradiation, the resin will be cured continuously from the side directly exposed to light towards the other side. As a result, nonuniform shrinkage stress is developed inside the solidified sample, which bends the film along the light path. This bending can be controlled by the irradiation time as well as light intensity.

RG: What was the biggest challenge?

Qi: The first challenge was to find the mechanism that makes the resign bend when exposed to light. We did experimental and theoretical investigations to understand this phenomenon. Once we understood it, we could precisely control the bending behavior. It was also challenging to make more complex shapes. The one-sided approach was developed at the very start, but then we started looking at a two-sided approach to create more complex structures.

A grayscale pattern used to create a self-folding flower is projected into a glass container. Light from the pattern forms a solid polymer which is differentially crosslinked, creating stress in the material. The structure folds when it is removed from the liquid. Credit: Rob Felt, Georgia Tech.

RG: How complex can you make the origami?

Qi: We made quite complex origami structures. Examples include flowers, Miura-ori folding, and cranes. Currently, it’s difficult to create really large structures, because our method mainly deals with thin polymer films.

RG: What applications could this have?

Qi: This method could be used to fabricate soft origami machines, mechanical metamaterials, as well as some capsule structures. As the material is not strictly confined, it can actually be applied to many comparable material systems.

RG: Is this something that anyone can do? What do they need to do it?

Qi: The method is very simple. You need a commercial projector and some photocurable liquid resin that has shrinkage behavior, a common property. The grayscale patterns could be created by software like PowerPoint.

Featured image credit: Rob Felt, Georgia Tech.