In many sectors, the energy transition is intertwined with innovative materials. Over time, laboratories have identified new materials that offer huge potentials. Some are self-healing, while others can even be programmed. The ultimate goal? To develop materials that provide more energy than they consume. Spotlight on innovative materials to watch in 2020.
Innovative self-healing materials
The principle. As the name suggests, these materials have the ability to self-heal, to “mend” themselves. So they don’t require any prior wear or defect diagnosis.
There are four types of self-healing materials:
- materials containing healing agents (embedded micro-capsules)
- microvascular materials, in which tubes carry the healing agents to a crack or flaw using pressure differential
- shape-memory materials
- reversible polymers
The challenge. In the construction sector and industry, the time and effort to track down defects can, at times, represent colossal costs for companies.
What stage are we at? Self-healing polymers first saw the light of day at the start of the millennium, particularly in reversible polymers such as rubbers. Twenty years on, research on the topic has progressed substantially. In 2017, Japanese researchers even invented a self-healing translucent polymer, a first step towards the development of self-repairing “glass” (1).
Innovative programmable materials
The principle. With integrated fibres connected to sensors and actuators, some polymers are able to change their form or behaviour depending on temperature, light, electricity, humidity, vibration or on contact with particular products.
The challenge. For the automotive or aerospace industries, as well as for construction, innovative materials such as these allow dynamic structures to be conceived without the need for robotics. They can also make such structures more ergonomic and comfortable. In addition, anti-vibration devices allow the working life of mechanical systems to be extended.
What stage are we at? Research and development are continuing. In 2013 however, American researchers developed the concept of 4D-printing (the fourth dimension being time), opening the way to new programmable materials, particularly at small scales such as medical implants or “soft robotics”.
The bioplastics of the future
The principle. A bioplastic is one which is wholly or partially bio-sourced. When it’s biodegradable (not necessarily the case), it can be composted. There are three categories of bioplastics:
- Bioplastics which are biosourced but non-biodegradable
- Bioplastics which are biosourced and biodegradable
- Bioplastics which are derived from petroleum but are biodegradable
The natural resources employed in the creation of bioplastic include sugarbeet, maize starch, sugar cane, wheat, flax, and many others.
The challenge. Faced with the worldwide over-production and over-consumption of plastics — a significant source of CO2 emissions and pollution — the need for innovative alternative materials has never been more urgent. Bioplastics are presented as one of the short- and medium-term solutions.
What stage are we at? Only 1% of the 360 million tonnes of plastics generated on the planet each year are bioplastics, according to European Bioplastics. This proportion will continue to rise over coming years as innovation continues to deliver new solutions.
Insulation from mushrooms
The principle. We’ve recently found a way to create insulation from mycelium, the vegetable filament system found in fungi which is known for its connecting strength. The concept is to grow mushrooms on vegetable waste, which nourishes and knits together the mycelium.
The challenge. “Mushroom insulation” is tough, fireproof and effective, as well as being biodegradable. Its production uses 7 times less energy than that of expanded polystyrene (2).
What stage are we at? Interest in mycelium extends all the way into NASA’s ranks. That’s right, The American space agency is considering using innovative mushroom-reinforced materials to build future human habitats on Mars! (3)
Sustainable alternatives to concrete
The challenge. Concrete production generates almost 7% of global CO2 emissions. Most of the energy used during the process is in the production of clinker, the main component of cement. That’s not taking into account the other natural resources (water, sand etc.) that it consumes. So substituting Portland cement, the most widely-used form today, has become a leading environmental challenge.
What stage are we at? Alternatives to Portland cement are emerging. These include:
- Clay cement, based on re-creating stone from clay by employing a low-energy alkaline molecular reaction.
- Fibre cement, in which vegetable- or waste-derived fibres are mixed in to halve the amount of actual cement required.
- A composite based on desert sand. Finite, a British start-up, has found a way to use the inexhaustible supply of desert sand to create a concrete with at least two times less carbon impact.
- Translucent concrete. An engineering feat offered by an Austro-Hungarian company, LiTraCon concrete allows the passage of light by incorporating optical fibres. For now, however, an extremely expensive material.
Graphene, a material with unfulfilled potential?
The principle. Discovered in 2004, graphene is derived from graphite. It comprises a sheet of carbon atoms arranged in a hexagonal pattern, so it’s no thicker than a single carbon atom. Called by some a “miracle” material, it’s extremely tough — 200 times more so than steel (4) — as well as being almost transparent and having exceptional electrical and thermal conductivity.
The challenge. An unbeatable innovative material, graphene could be the ideal replacement for silicon in transistors and computer componentry, or could even be the key element in future electrical storage batteries. Its transparency means it’s also expected to feature in touchscreens, visual displays and solar panels, and it can also be used to make plastic electrically-conductive.
What stage are we at? Large-scale production of graphene remains complex and very expensive. However, research is in full swing — particularly in Europe via the European Commission’s “Graphene Flagship” programme.