But now metamaterials are cropping up in products we already use, and in the policy agendas of countries that see strategic value in controlling the next generation of materials engineering. Prior to 2010, fewer than 1,000 patent applications mentioning metamaterials were made each year. But in recent years, that figure has spiked to nearly 4,000.
The meta moment
The reason for this is the increasingly common use of metamaterials in our everyday lives and products. In smartphones, metamaterials engineered with nanoscale patterns can precisely manipulate light waves instead of traditional camera lenses. In speakers, plastic lattices made of metamaterials are stripping away stray sound to make audio clearer. And on rooftops, photonic films made of metamaterials are mirroring unwanted heat from the sun away from the planet.
Metamaterials are having a moment – and their future looks bright. But what exactly are they? “Metamaterials are materials where the structure does the trick, and the trick is that it gives you properties you wouldn’t have in nature normally,” says Gianluca Memoli, an acoustics researcher and entrepreneur who straddles academia and industry. Memoli runs Metasonixx, an audio-focused metamaterials firm, while also being associate professor in sound-based interactions at the University of Sussex.
The structures that give metamaterials their trickery are engineered to be shorter than the wavelength relevant to the problem, whether that’s light, sound or vibration, which is why “they require engineering and manufacturing at sub-wavelength level,” he says.
Metamaterials derive their properties not from their chemical composition, but from their internal structure. The way that metamaterials’ meta-atoms are arranged gives the material abilities greater than the sum of its constituent materials.
That engineering challenge – and how to ensure the UK benefits from its prime position to develop metamaterials – is the subject of a new policy report from IMechE and the UK Metamaterials Network (UKMMN). The report sets out five buckets of work – from funding and skills to standards and scale-up – while highlighting examples of best practice already extant in manufacturing, health, sustainability, and the UK space and aviation sectors.
Moving from party tricks to products
In consumer optics, researchers have demonstrated that flat ‘metalenses’ can compress conventional camera modules into hair-thin wafers patterned with nanoscale features. The technology helps focus a range of wavelengths from a source over a large diameter, making images clearer while making lenses smaller.
In hi-fi speakers and other audio products, metamaterial absorption technology is being used to get rid of unwanted sound reflections and reduce distortion, providing better audio quality. Memoli’s Metasonixx builds soundproof panels of the type that can be used in offices as desk dividers, taking advantage of metamaterials’ properties in blocking out sound.
The sports sector has also adopted the tech wholeheartedly. British start-up Rheon Labs has developed shear rate-dependent mechanical metamaterials that are naturally soft and flexible but stiffen rapidly upon impact – qualities that make them useful for flexible body armour and helmets for sports and motorbikes, as well as in clothing for rate-dependent tension control, such as sports bras, and vibration damping in Padel rackets.
That also extends to the medical sector. Osstec, a spinout from Imperial College London, is developing a new generation of knee replacement implants made from additively manufactured titanium lattices. Osstec uses metamaterials designed to mimic the structure of human bone, leading to more reliable replacement joints to improve patient recovery. Shape-morphing and multi-stable metamaterial implants are also being deployed in cardiac stents, allowing a small device to be implanted and then deployed to full size to unblock arteries.
Osstec is developing knee replacement implants from additively manufactured titanium lattices
These examples are far from exhaustive. The new IMechE report highlights dozens of academic advances, which has financiers interested in the sector. For investors, metamaterials are no longer a curiosity. “We are investors. We are in the business of making money,” says Conrad Burke, managing partner at MetaVC Partners, a US-based venture capital group that has backed a portfolio of around a dozen companies built on metamaterials.
“We believe that metamaterials is a really remarkable breakthrough area,” he says. “They can make products that exist today smaller, faster, using lower power, and they also breed a whole new generation of new products. We’re excited about metamaterials because it has huge, broad-based applications in so many areas, in multibillion-dollar markets.”
Burke’s engagement with metamaterials is for good reason, and he’s blunt: “It is happening right now.” Some of the companies he’s backing are already generating “millions and millions of revenues,” he says – proof that the technology is already here and no longer hypothetical. But to take advantage of the opportunities requires what he describes as a familiar “cocktail” of risk appetite, access to capital and a support system that links universities to markets.
“That’s the cocktail that works here in Silicon Valley,” he says – and it can work for the UK too.
Championing homegrown talent
The UK has plenty of pedigree in metamaterials. Burke points to Imperial College London’s Sir John Pendry as a field-defining figure – a “Galileo of metamaterials expertise” – and praises the UKMMN for coordinating universities across disciplines, with particular strength in acoustics.
“We see hotspots of metamaterials innovation in the US and in Asia. But the UK, in terms of Europe, is really up there in my mind,” he says. It’s not just single totemic figures that are leading the sector either: from 2018 to 2021, the UK was ranked as world-leading for research impact and quality based on field citation ratio, and fourth worldwide for research output from 2018 to 2022. The UKMMN has more than 1,000 members from different backgrounds.
If there’s a limit for progress in metamaterials, it is in manufacturing. Many photonic metasurfaces and mechanical lattices demand feature sizes measured in nanometres to tens of microns. That is doable in university labs, but takes investment to produce at the rate or cost needed by industry. The IMechE report says the UK needs multiscale production facilities and a workforce to meet expected demand.
A close up of an injection moulded piece from Rheon Labs
“It’s not just the material,” says Memoli. “The base material that does the trick is the engineering and the design of it.” The shapes required are “non-trivial” and only recently manufacturable at the required scale. “In my field, it wouldn’t be possible to have metamaterials without 3D printing,” he says. “As 3D printing became more and more easy to have in your lab, then you could do more structures.” Once tested at a small scale, it’s possible to move to mass production techniques like injection moulding for acoustics, or established lithography flows for optics.”
Dr Tom Allen, a mechanical engineer at Manchester Metropolitan University, connects the technical to the regulatory aspect. Allen, who helped lead the IMechE research, believes that industry–academia partnerships are needed on grants alongside investment that takes designs from idea to scale-up.
“A key thing is embedding manufacturing in from the start,” he says. “So when you’re designing a metamaterial, you’re thinking about how you’re making it.”
The UK’s assets are significant: we have a top-tier research base, a cross-disciplinary UKMMN and early credibility from companies already making waves in this space. And money is beginning to meet the moment. Earlier this year, the Henry Royce Institute announced £1m for metamaterials scale-up projects, and the MetaHub has recently launched with nearly £20m of funding at the University of Exeter.
Burke’s advice from the investor side is to double down. “Now that you’ve secured funding, go back to Westminster and start shaking people down for even more,” he says. Doing so can turn what he calls the “plethora of innovation” in UK universities into a burgeoning industry.
Putting design first
That industry relies on a simple design philosophy: use geometry alongside chemistry to get the behaviour you need. “What’s really useful about metamaterials isn’t necessarily that, like traditional materials, you say: ‘Steel is really good because it’s strong, or plastic is really good because we can mould it easily’,” says Burke. “We take our base material, and then we change that into a metamaterial and design it for a very specific application.” That can make things smaller, more compact, lighter or able to expand in a certain way when pushed or pulled.
It’s in large part what makes metamaterials such an exciting innovation. And Memoli thinks the UK can and should own a significant chunk of the future. “I’ve been working in metamaterials now for 10 years,” he says. He believes this is “a UK story” worthy of pride.
“The UK recognised them first,” he explains. “We started using top-level science first.” But he also worries that the UK risks “losing at the last 100 metres of the run” if the country fails to bridge the gap between the lab and the market.
A Ventete bike helmet, made with Rheon Labs metamaterials
Capitalising on the imminent metamaterials boom requires calculated risk-taking, something that makes governments and researchers alike traditionally wary. But they ought not to be, according to those closest to the industry. “This is actually a great time to start a company,” says investor Burke. However, as the IMechE report makes clear, people must take risks and push the technology forward to capitalise on opportunities.
The stakes are high. The global market value for metamaterials is projected to grow to more than $10bn by 2030 and $15bn by 2035 – and the UK could capitalise on that. Because metamaterials are the building blocks of products, they’re not a big-bang material seen by all and sundry.
“I think it’s going to be quite, quite subtle,” says Allen. “Metamaterials are almost a behind-the-scenes sort of technology.” But this makes them no less important. “We need brave people to start companies trying to sell the dream in a language that everyone can understand,” says Memoli.
IMechE and the UKMMN have produced a report to raise the profile of metamaterials and highlight the opportunities they offer in different sectors, including healthcare, energy, aviation and space. The report launch will be hosted at One Birdcage Walk on 1 December. Find out more and register.
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Content published by Professional Engineering does not necessarily represent the views of the Institution of Mechanical Engineers.