Graphene is carbon formed in an ultra flat, thin and uniform sheets that, weight-for-weight, is 200 times stronger than steel, almost as electrically conductive and chemically resistant as gold, as flexible as rubber and as tough as diamond. Because of these many useful properties, its discovery has led to many searches for ways to construct things with it that apply its ultra-thin layers in the most functional and economic ways. Assembling it using 3D printing technology seems an obvious line of exploration.
Researchers have been working on various kinds of 3D graphene inks for some time, especially with a view to producing a spectrum of new batteries, super capacitors and better solar cells. However, they have had limited success, as there is a difference between 3D inks that combine fragments of graphene into thermoplastics like ABS and constructing pure sheets of graphene into 3D shapes. The heat involved in many 3D printing methods, such as in laser sintering, can be destructive of graphene’s properties too.
Techniques on the horizon promise new ways to create graphene, or at least graphene-based structures, that realise the material’s potential more effectively.
One such project, carried out by a research team at the Delft University of Technology in south Holland, uses an ink based on bacteria. Drawing on ideas from biotech, where 3D printers are being used to create foodstuffs and living tissues, the team developed an ink combining a chemical precursor, graphene oxide, with bacteria that can convert it into a firm graphene-like structure. The printer is deliberately simple, a kind that can be found in any 3D printing bureau, with only minor adaptations such as removing the heating element.
Dr Anne Meyer of Delft’s Department of Bionanoscience says: “One of the big advantages of using bacteria is that it’s cheap, easy, and environmentally friendly… there’s none of the chemical waste that you have with some of the traditional chemical approaches”.
Although prices currently argue against using the method as a means of mass producing graphene, 3D printing straight into finished products is a different ballgame entirely. The technique may be able to produce components and circuits in 3D on small scales, using very simple and lightweight equipment.
Light weight is important because the Dutch team has one eye on future application of the technology in space. The same piece of equipment might even be used to print objects, circuits, foods and medicines on space stations or during the long-awaited trip to Mars. The team is already looking to use similar bacterial methods to extract and utilise silicon and iron from lunar dust. Dr Meyer envisages space factories “stocked with 3D printers and staffed by bacteria”, so if you want to open the first 3D printing bureau in space, now may be the time to book your ticket with Elon Musk!
Another possible breakthrough in creating graphene structures by reduction of graphene oxide in 3D inks has been announced by researchers at the Korea Electrotechnology Research Institute (KERI) in Seoul. The team claims that its method lets them print nano-structures and wires with the full strength and electrical properties of 100% pure graphene.