What the future is made of

Human-made materials affect our everyday lives. Just take a look around you: smartphone, earplugs, the seat in the tram. It is nearly impossible to list all materials used in these objects. Just a hundred years ago, the total weight of man-made things, the 'anthropogenic mass', amounted only to approximately three per cent of the global biomass. Today, there is much more man-made material on Earth than living beings. And every week, an amount of artificial material is added that corresponds to the total weight of the world's population, according to a study published in the journal Nature.

Meanwhile, research groups all over the world are searching for new materials: Our hopes are pinned on them to solve many burning issues of our time. The development of sustainable materials for energy storage, degradable or recyclable synthetic materials or an environmentally friendly semiconductor technology is particularly urgent.

To each era its own material

Since the beginning of human history, the discovery of new materials has determined the course that society would take. Stone Age, Bronze Age, Iron Age: Entire eras were named after important materials. "Experimenting with various materials is as old as humankind," says archaeologist Christiana Köhler from the University of Vienna. And today, the material culture left behind by our ancestors sheds light on their ways of living and on the economy at that time: “Every object contains knowledge of raw materials, materials and skills."

Christiana Köhler, who conducted research in Helwan, an ancient city south of Cairo, for many years and is currently leading excavations in Abydos, Egypt is mainly interested in the life and work of common people 5,000 years ago. "We have uncovered a huge cemetery in Helwan. The objects we found there tell us that the population was well-nourished and worked hard and that participation in the common infrastructure seemed to work well."

Every era is characterised by its typical artefacts and materials. The raw materials put to use are particularly interesting in this regard. Based on the example of ceramics, Köhler elaborates, "To make ceramics, you need water – a very valuable resource especially in arid regions – as well as fuel. The furnace has to reach a temperature of at least 650 degrees Celsius. Where did people get the fuel? Who made the objects? An entire catalogue of questions comes to our minds, taking us deep into the society and economy of the relevant time."

Ceramics through the millennia

According to Köhler, the material of ceramics has shaped us most strongly, from a historic perspective: "There is hardly anything more resistant; the oldest known ceramic artefacts are almost 10,000 years old." It is staggering that humans have discovered how to create a resistant material from clay or loam by firing it pyrotechnically at a high temperature so early on in their history – a milestone with regard to the preparation and storage of food. 

Today, thousands of years later, ceramic is still part of our everyday life – and its potential has not been fully exploited yet. Due to their numerous, excellent properties, ceramic materials are being used in a wide variety of ways and are considered promising materials of the future, for example, in the area of energy storage or even for space travel. 

The hype surrounding new materials

Rediscovered, further developed or new: The surfacing of a promising material is usually followed by an initial hype, explains Thomas Pichler, head of the Electronic Properties of Materials research group at the Faculty of Physics. At the beginning of the 1990s, everybody was talking about fullerenes, spherical molecules consisting of carbon atoms; graphene and other two-dimensional materials, such as transition metal dichalcogenides (TMDCs) have been high on the list for a few years now. "The latest designer materials are layer structures of two-dimensional materials that are stacked at an exact angle, giving them completely new properties, such as superconductivity," explains Pichler. 

From the Valley of Delusion to the Productivity Plateau

This phase full of hope during the discovery of a new material is characterised by an exponential increase in academic publications and media coverage and lasts five years on average. "In this time, possible applications are explored before the hard work of optimisation begins to ensure that the predicted properties can actually be exploited."

According to Pichler, only the most promising applications remain in this so-called Valley of Delusion and only the 'most tenacious' researchers keep the ball rolling to further develop the materials for specific applications on the subsequent Plateau of Productivity. "It sometimes takes another ten to fifteen years until industrial production can start."

The crux: No matter how promising a new material is, to be interesting for the industry it has to fulfil many criteria, for example, that it can be produced at a large scale and is affordable and non-toxic – consequently, the materials actually put to use may often have only a small fraction of the theoretically possible properties. "In the end, the result is often a mixture that is only a few factors better, but cheap enough to go into mass production. It is our task as researchers to show which materials are worth being improved."

Probably the strongest material in the world

Thomas Pichler is one of those who kept the ball rolling in the area of nanotubes – one-dimensional, tube-like structures at microscopically small scale which are being used in a variety of ways today. His research now also focuses on designer materials made of two-dimensional layer structures and on their connection with nanotubes. 

The physicists at the University of Vienna have already caused a hype once: In 2016, Pichler and his team were able to create the longest, stable one-dimensional carbon chain back then, thus proving the existence of carbyne. Researchers had been searching for this material for 130 years. It is considered the strongest material in the world, outperforming diamond, graphene and nanotubes in many respects. "However, when a company calls you and asks whether they could order a few kilograms of carbyne – which actually already happened – I have to put them off unfortunately," says Pichler smiling, "We have really only a few micrograms of it here in the laboratory at the University of Vienna."

Understanding material properties at the atomic scale

This small quantity suffices for the physicist to be able to concentrate on his research focus: the analysis of material properties. "Only when we understand these down to the smallest detail, at the level of atoms and molecules, we can improve them in a targeted way", Pichler stresses. This also requires the development of new, ground-breaking methods to investigate the ever smaller, ever finer materials. "And this is what we are especially good at here at the University of Vienna," says the scientist who has received numerous awards and who enjoys tinkering with improving research equipment as much as he enjoys using it.

Thomas Pichler and his team are currently involved in MORE-TEM, a large-scale project funded by the EU in which they work on the development of an electron nanospectrometer that should make it possible to identify the properties of various modern nanomaterials for the first time. For example, to understand what actually happens inside a battery. Or to provide the basis for the development of a superconductor that is able to conduct electricity under everyday conditions without any loss, which is considered the holy grail of materials science. (More about Thomas Pichler's research in the video)

Materials research following a modular principle

Modern materials research aims to make the properties of materials controllable at the nano scale, "To achieve this, we basically play Lego with them: We fit the molecules together in different ways and thus change their properties," explains Jia Min Chin, group leader at the Department of Functional Materials and Catalysis at the Faculty of Chemistry. Her special 'playing field' are so-called metal-organic frameworks, MOFs in short: molecular materials that consist of both organic and inorganic molecules and combine 'the best of both worlds' according to Chin.

MOFs are 1,000 times smaller than a grain of sand. Their surface, however, is very large: One gram of the material can have a surface of more than a soccer field, corresponding to an area of around 8,000 m². "This is due to the surface of its pores which resemble those of a sponge", say the young chemist, who has conducted research in Singapore and England has obtained here PhD from the M.I.T. under the supervision of Nobel Prize laureate Richard R. Schrock.

The small particles are also extremely versatile: "You can combine them following a modular principle and in a very precise way; every piece has a very particular property – you can imagine this like designing a car with special features at the molecular level." In her current project, Chin investigates how the promising MOFs can be manipulated in a targeted way by means of electromagnetic fields.

Inspired by nature

For her research, Jia Min Chin likes to draw inspiration from nature. In a current project, Chin and PhD candidate Tanja Eder have taken a carnivorous plant's mechanism to capture prey as a model for solving a long-standing problem in aviation together with partners in the industry: "Keeping the wings of an airplane free from ice previously required many chemicals and a lot of energy. We were able to develop a new surface from which forming ice simply slides off." The researchers drew inspiration from the slippery edges of the traps on the leaves of the tropical pitcher plant (Nepenthes).

"Copying natural structures in the lab is one of the greatest challenges of materials science," emphasises the chemist. Seashells or bones, for example, have a brilliant, highly complex architecture that can withstand a wide variety of strains. Although it has not yet been possible to reconstruct them, scientists all over the world are trying to understand nature's tricks and learn from them. "In particular, when it comes to the development of sustainable, recyclable materials, nature is unbeatable."

Welcome to the age of plastic

Recycling is the key word taking us to the Department of Science and Technology Studies at the University of Vienna. Here, social scientist Ulrike Felt and her team are investigating the processes leading to the emergence of new materials, the promises associated with them and the 'collateral futures' at the end of a material’s innovation phase. "Unfortunately, we as a society usually start discussing the life of materials only after they have fulfilled their primary purpose only when it is already too late," says the social scientist with sorrow. In her current project Innovation Residues, she investigates the remnants of major fields of innovation. 

"The example of plastic shows that materials are able to change entire societies and create new dependencies," explains Felt. Plastic became available to the mass market in the 1950s. Since then, production has increased 230-fold according to the OECD. Even if the versatile material has become crucial and seemingly irreplaceable in many areas of life (only think of medicine): Plastic waste is one of the greatest environmental problems of our time. Tiny plastic particles can already be found at any remote place on Earth and even in our bodies, with still unforeseeable long-term implications.

However, taking synthetic materials out of circulation is currently almost impossible, says Felt. The Single Use Plastic Directive, which entered into force in 2019 and prohibits the distribution of certain single-use plastic products, such as plastic straws or plastic bags, is an attempt to reduce the amount of unnecessary plastic. A beginning that, however, often finds an end already within the EU and at the EU borders: "We need policy-makers who are more courageous and willing to impose more far-reaching measures," says the researcher of the University of Vienna.

What is our future made of?

Which material will leave its mark on the next era remains to be seen. For every material, there are various specialists who are adopting different approaches. One of them – or maybe a combination of several? – will ultimately prevail.

The researchers agree that interdisciplinary cooperation is especially important in this context: To solve the complex issues of our time, we need to think outside the box and establish and maintain collaboration on a broad front in research, and between academic research and industry. "In the process, we have to consider from the beginning what we want and do not want to knowingly leave behind," the archaeologist and the chemist agree.

We can already say this much: The one perfect material of the future does not exist, at least not from the perspective of materials research, says the physicist, "You can always further improve any material!" Science, politics and society have to jointly consider the framework in which this happens, concludes the social scientist. After all, "Ultimately, we as a society decide what will be the material of the future."