GRAPHENE: ORIGAMI AND KIRIGAMI

The Art of Origami and Kirigami comes into the world of Electronics with Graphene

A graphene sheet may be folded in the same way of a sheet of paper; for this reason, flexible electronic circuits, microscopic robots and three-dimensional structures at nanoscale, based on graphene, represent devices that could be obtained by applying the same folding rules of an origami.

The art of origami and the ancient Japanese art of kirigami are being used as a guide by scientists for the future of Electronics. By means of the kirigami technique, a sheet of paper is carved and folded, to obtain three-dimensional objects and particularly “elastic objects”. This technique has been already applied in the realization of extensible conductors, made of carbon nanotubes.

Currently, the scientists are using the technique of origami and kirigami as a starting point in the implementation of electronic devices, made of graphene, such as: smartphones, tablets and watches, with the characteristic of being wearable, flexible and foldable. They could change shape without being damaged or destroyed, due to the rupture of the rigid conductors currently used.

Look at the video: Graphene Kirigami

Last year a group of Chinese scientists, using several layers of graphene oxide, built a robot, applying the folding rules of the origami. This robot-origami, made of layers of graphene oxide, is permeable to water molecules; the composing strips act as sponges and swell, absorbing the moisture from the air. If these strips are exposed to the heat or to the near-infrared light, they release the absorbed liquid very quickly and, consequently, they contract and fold back on themselves, advancing on the supporting surface.

Look at the video: Carbon-based paper that walks when hit with a laser

Recently Itai Cohen and his team of “Cornell University” have examined a single graphene sheet, covered with a layer of silicon dioxide (SiO₂) and having thick half a nanometer; they have noticed that the silicon dioxide reacts with the carbon atoms of the graphene in different ways. It depends on whether the silicon dioxide is heated, crossed by an electric current or soaked in liquid with different pH. This behavior of silica has allowed the researchers to control the expansions and contractions of graphene and has allowed them to fold it, according to predefined patterns. The aim of the scientists is the realization of tiny electrical circuits that should be printed on a sheet of graphene, able to absorb light and generate electric current, when it is folded into a three-dimensional structure. Should the scientists be able to realize a processor with those characteristics, the calculations could be performed bringing back the result in the form of light at different frequencies.

The “Miura-ori” is another technique of folding paper; it is used, in particular, in the aerospace sector, but also in the control of the fundamental physical properties of any thin sheet of material, such as graphene. It is a method that consists of folding a flat surface, such as a sheet of paper, in a smaller space, in order to optimize the volumes. The name comes from its inventor, the Japanese astrophysicist Koryo Miura.

Since 2014 the Spanish scientist Tomas Palacios, head of the “Center for Graphene Devices and 2D Systems” at the “Massachusetts Institute of Technology” and one of the most innovative researchers who deal with graphene, has been working with his team on the possibility to create new objects in graphene, with electrical components integrated inside, using 3D printers. In practice, the scientists want to integrate the graphene into the objects that are printed; this idea is one of the most advanced in the study of this material.

Look at the video: Tomás Palacios: 2D Materials and Ubiquitous Electronics‬

The aim of Palacios is also to create "origami of graphene", that is layers of materials that are folded in a similar way to organelles, the tiny structures that we can find in the cells. If this happened, a large amount of computing power could be stored in a tiny space.

The correlation between "Origami and Nano-structures” is also subject of study for a group of scientists of Harvard University; they have used synthetic DNA molecules to obtain "prints" for nano-structures, that can be used on graphene sheets. The scientists have constructed real origami, modeling the double helix of DNA, and then they have used the origami as “prints” on graphene sheets, to draw nanometer-size structures of particular shapes. The use of "DNA masks" seems to be a possible technique for the production, on a large scale, of new generation transistors, based on graphene.