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What's new in R&D: from a glue to hold planes together to self-repairing clothes
By Duncan Jefferies
An enormous amount of innovation goes on behind the scenes in labs to make everyday items more efficient and sustainable. We look at four materials with far-reaching applications.
A Neanderthal spear has two main parts: a piece of flint for the point, and a stick for the shaft. These were attached with tar from birch bark, which Neanderthals probably extracted by placing a roll of bark on an open fire. In other words, they invented the world’s first known glue around 200,000 years ago.
Their discovery led to the creation of other compound tools such as hoes and axes, which shaped the development of early human societies. Jump forward to today and adhesives, self-repairing fibre, graphene and other forms of material innovation allow us to achieve things that would have seemed unimaginable to our ancestors. So what research and development is going on behind laboratory doors?
Adhesives
In 2017, a team of scientists and engineers from consumer and industrial goods company Henkel demonstrated that three grams of adhesive could effectively pull a 208-tonne freight train. Loctite HY 4070 – a hybrid adhesive that combines several technologies for improved bond strength, durability and curing speed – was used to fuse two locomotive cars together. The team behind the demonstration watched nervously as the train set off. Incredibly, the adhesive held.
The experiment showed that hybrid adhesives are not only strong, but can also withstand considerable shocks, friction and vibration. That makes them ideal for the automotive and aerospace sectors, where joints and seals need to be extremely durable. The fact that Loctite adhesives can replace welding also makes them an important tool for manufacturers that are “lightweighting” their cars and planes – ie substituting heavy metal materials for carbon fibre, plastic and aluminium – which can improve fuel efficiency and the battery range of electrical vehicles, for example.
“If you try to weld carbon fibre, you will not get very far,” says Dr Kourosh Bahrami, corporate vice president at Adhesive Technologies. “Even if you try to weld aluminium with steel, it will not work. And that’s where adhesives come into play, because they enable you to bond multiple substrates. This not only counts for the manufacturing of industrial goods but also when it comes to maintenance and repairing.”
Adhesives also make smartphones safer to use. “The typical adhesives that are used in a smartphone provide additional functionalities beyond the bonding. Many solutions, for example, have thermal properties that insulate the battery or protect the device from overheating,” says Bahrami.
Adhesives are also a vital part of touchscreens and fingerprint sensors – even circuit boards and other electronic components. They’re found in the sensor arrays that help self-driving cars to see what’s around them. And Henkel’s electrically conductive adhesives are also helping engineers create more efficient and reliable solar cells.
Fibres
Synthetic fibres such as nylon, acrylic and polyester have transformed the clothing industry over the past 60 years. But the way these materials are produced and disposed of has far-reaching environmental impacts. Synthetic fabrics are a major source of microplastics pollution, for example, and many are made from fossil fuels such as oil and coal.
Natural fibres aren’t squeaky clean, either: cotton production uses a lot of pesticides and water, for instance. Researchers are therefore trying to develop more sustainable textiles from everything from waste pineapple leaves to leftover coffee grounds. A company called Singtex collects the latter from major coffee vendors, combines it with a polymer and spins it into yarn that can be used for outdoor wear and bedspreads.
In the future, your clothes may even be able to repair themselves. Tandem Repeat, an Early Bird winner of this year’s Global Change award, has created a thermoplastic fibre that incorporates the self-healing characteristics found in squid genes. Fabrics created from these fibres also act as a glue, minimising the shredding of microfibres during washing.
Researchers at Chalmers University of Technology have even developed a fabric that converts kinetic energy into electric power. It works better when it’s wet, so one day your sweaty gym clothes could theoretically help to power your smartwatch.
In the future, your clothes may even be able to repair themselves.
Graphene
Graphene is the world’s first 2D material, meaning it is comprised of a single sheet of atoms. More importantly, it has amazing strength, electrical conductivity and heat conductivity properties, which has led to it being called a “miracle material”.
“Graphene can improve consumer products in two ways,” says Dr Aravind Vijayaraghavan, reader in nanomaterials at the University of Manchester. “First, by making existing products better, and second by enabling new kinds of products that currently don’t exist.
“For example, graphene can make existing rubber and plastic products stronger and more durable, which has both performance and environmental benefits. Graphene can also enable things such as flexible displays, super-high-capacity batteries and high-efficiency water purification.”
Two researchers at the University of Manchester, Prof Sir Andre Geim and Prof Sir Kostya Novoselov, were the first scientists to extract graphene from graphite, winning the 2010 Nobel Prize in physics for their work.
Since their discovery, many of patents for graphene-based consumer products have been lodged, and some of these items are now beginning to appear on the market. For example, the footwear company Inov-8 has released a running shoe with graphene-enhanced rubber outsoles, which they claim are 50% stronger than standard rubber ones.
Batteries
Most of us have suffered the frustration of having our phone die in the middle of an important call. But in future the batteries that power our smartphones, and potentially our cars, could have much longer lifespans.
Solid-state batteries are one of the most exciting areas of research, and a “very attractive long-term battery goal – one that would benefit the consumer electronics market,” says Allan Paterson, head of programme management at the Faraday Institution.
Solid state batteries are more stable and safer than the lithium-ion batteries that currently power most electronic devices, and their higher energy density means your laptop or smartphone would last for much longer between charges.
“If deployed in electric vehicles, weight reductions and increased energy density would improve driving range and lower costs,” says Paterson.
Sodium-ion batteries also show promise. Rather than lithium, which is relatively rare, they use salt, the sixth most common element on Earth – and could be up to seven times more efficient than current batteries.
But before you start dreaming of a smartphone that doesn’t need charging every night, you should note that Paterson says: “There are still a number of complex challenges that need addressing to drive forward the next generation of battery technologies.”
Solid-state batteries are one of the most exciting areas of research
