We have all heard of smartphones. Smart homes are starting to enter our consciousness with fridges that know when to order more milk and thermostats that learn your heating preferences. Not on most people’s radar though are smart materials. This could be about to change as it is an industrious area of research and development.

The definition of smart materials is any material with properties that can be significantly altered on demand by external stimuli. It is a huge field of cutting-edge research. The global market for smart materials in 2014 was $26 billion. By 2019 it is predicted to be $42.2 billion. If you are working with smart materials in the UK, you should definitely be finding out how the government could help with funding. You could recoup up to one third of your qualifying R&D expenditure.

There are many ways in which smart materials can be manipulated and just as many stimuli that can manipulate them. The potential number of applications that this leads to is rather exciting: self-healing glass, the replacement of motorised components, armour that gets stronger in accordance with impact…

Piezoelectrics – a smart material with a history

One example is piezoelectric material. This is the phenomenon of a crystal (any solid material with an ordered atom structure) generating voltage when pressure is applied to it. The reverse can also be true: where applying voltage to a material can give off pressure which manifests itself as movement. While many smart substances can be thought of as next generation, piezoelectric technology has been around for decades. For instance it was one of the technologies behind the development of sonar and also explains how quartz watches work.

Application of shape memory alloys

Another group of smart materials are known as shape memory alloys. Heat, electricity, magnetic fields or stress compel the material to change shape before returning back to the original shape. Chevrolet recently introduced this to the Corvette. At first glance the application may sound a little mundane especially on such an exhilarating car – it was a mechanism to help close the boot (or trunk as they call it stateside). Heat generated by an electrical current stimulates a shape memory alloy wire to move and open a vent that aids closing the boot. Hmmmm.

But it gets a bit more interesting when you consider that it replaces an electric motor and is about half a kilogram lighter. Furthermore that there are about 200 motorised parts on a typical vehicle so the potential for making cars simpler and lighter using smart materials is enormous. This could lead to better fuel efficiency and lower running costs for consumers.

Indicating just how big an impact smart materials may have, Paul Alexander, smart materials and structures researcher at General Motors (the parent company of Chevrolet) said: “The shape memory alloy used on the new Corvette represents nearly five years of research and development work on smart materials for which GM has earned 247 patents. And it is just the beginning. We have many more smart material applications in the pipeline that will bring even more improvements to our vehicles going forward.”

So many categories of smart material

We mentioned the wide range of smart material fields. Here is a lightening quick run-down of some of the main ones:

  • Magnetostrictive. That’s shape and magnetic fields.
  • pH sensitivity concerns volume and pH
  • Temperature responsive polymers are materials that can reversibly change following temperature fluctuation.
  • Halochromic is colour and acidity
  • Chromogenic systems  are colours and electric/optical/thermal stimuli
  • Photo-mechanical is shape changing caused by exposure to light
  • Polycaprolactone. A complicated one, it refers to: shape moulding in hot water
  • Self-healing. Self-explanatory we hope.
  • Dielectric elastomers. Another complicated one: stretching properties and voltage.
  • Magnetocaloric is magnetic field and temperature fluctuation.
  • Thermoelectric. You could probably guess it: temperature and electric
  • Ferro-fluids. These concern directional flow and magnetism.

If that all sounds a bit abstract let’s shine a light on one to show some application – take the obscure sounding ‘chromogenic systems’. It hardly jumps out at you as an everyday thing. But actually, this is the technology behind Liquid Crystal Displays in our televisions, anti-glare rear-view mirrors in our cars and those eye glasses that darken to become sunglasses in sunlight – to name just three. So we probably all benefit from chromogenic systems in one way or another already.

Let’s look at some more categories of smart material in closer detail:

D3O making a big impact

The first case study we are going to look at is an exciting British company called D3O – also the name of its patented smart material. D3O (the material) is a next generation shock absorber offering impact protection solutions to an ever growing range of markets. The clever science bit is that its molecules go from a normal soft and flexible state, to locking together upon shock, before returning to their flexible state. In simpler terms it goes from gooey, to hard, and back to gooey when it endures impact. And the harder the impact the harder the material becomes. Clever stuff and here is a video to show just how remarkable it is.

Nice, but what can you do with it? Well it came on to our radar as an iPhone case. Most people nowadays have hundreds of pounds minimum invested in portable tech, and let’s be honest many take it rather personally when a phone or tablet get broken. D3O doesn’t offer any extra protection if you drop your phone down the toilet or in a mug of tea, but can work wonders if you drop it on a concrete floor by hardening to disperse the energy from the impact.

Helping Andy Murray win Olympic Gold

D3O’s application is far more widespread than protecting tech though. Its first commercial application was in kit for the US and Canadian Winter Olympic teams back in 2006. D3O claim that they revolutionised the global protective wear market overnight with their equipment’s low profile, light weight and flexibility. And when you look at the string of other sports wear applications it is hard to disagree. American Football, winter sports, boxing, horse-riding, baseball and tennis – The racquet that Andy Murray used to win Olympic Gold and the US Open had D3O technology incorporated.

Field testing: hitting someone on the head with a shovel

They have a large presence in motorcycle sportswear, and also in snowboarding where the technology can find a balance between protection and style. There are various video demonstrations online with people having fun testing the protective qualities of D3O. This journalist seemed to enjoy hitting a D3O executive on the head and knee caps with a shovel. Fortunately he was wearing discreet D3O armour.

Gizmag also did a very thorough review of D3O motorcycle elbow protectors vs conventional foam. This time it involved hitting elbows with frying pans rather heads than shovels. Perhaps what was most interesting from an R&D perspective was the response it sparked from D3O who explained they were working through many iterations to get different balances between comfort, style and level of protection for different markets. Great R&D in action!

Other applications of D3O include defence and law enforcement, footwear, and in industrial and medical use. D3O modify their product material for different applications and have a high tech lab in which they focus on product development, advanced and independent testing and rapid prototyping. A prime example of how once a next gen material is developed it is really just the start: there is often continuous research and development into its real world application.

Ferro-fluids and smart magnetics

Ioniqa are a Dutch company that specialise in magnetic smart material including Ferro-fluids elastomers and gels. One of the key features of magnetic smart material application is that they reduce the number of moving parts in machines. This has many benefits to end users. Durability increases because there is less wear and tear. There is greater energy efficiency through reduced friction. Performance is enhanced through a reduction in vibrations. And there is less negative environmental impact due to recycling of the magnetic smart materials.

Ioniqa are working on what they call a cradle-to-cradle PET (plastics) recycling project in which their smart magnetic separation process converts used PET into pure new raw materials. It’s a unique clean tech process that will contribute to a circular economy – A bright vision for the future.

Other applications that Ioniqa discuss on their website show again the range of uses of smart material: from the Audi Magnetic Ride which features Magneto Rheological Dampers that automatically adjust suspension based upon road conditions, to liquid sealants in computer hard drives. Other applications include contrasting agents in MRI scanners, separation agents in heavy industry, heat transfer in micro-systems based on thermomagnetic convection. It has even been rumoured in the past that Apple have been experimenting with magnetic smart fluids in their touch screens to give precise haptic feedback through the glass – when typing on the virtual keyboard for instance.

The world of self-healing materials

Our final case study is that of self-healing materials. These materials react to damage and heal themselves without human intervention – biological tissue from nature is the inspiration. Autonomic Materials – a US based firm – adhere to a strict definition whereby true self-healing only occurs with zero intervention, although as we will see later, other self-healing materials do require some manual oversight.

So what are the benefits? Unlike most of the other smart materials we have looked at, the name instantly conjures up images and applications. The most obvious benefit is durability of products in the field. Think big infrastructure. If a coating on an oilrig can heal itself it can save on repair bills, costly downtime and delay replacement costs. Such assets can cost millions of dollars each day that they are out of action.

Autonomic Material’s technology is based on dual microcapsules laced throughout paint coatings. The microcapsules are less than the width of a human hair. As the paint degrades or is damaged the microcapsules rupture causing a chemical reaction that repairs the paint. Simple yet clever. And as Autonomic Materials proclaim, it needs no manual intervention to work. They have developed their dual microcapsule to be applied through elastomers, thermosets and Powder Coatings to maximise its potential use. And the range of markets in which it can be used include Oil & Gas, Aerospace, Infrastructure and Marine among many others.

Vascular systems – that mimic the blood vessels in the human body – are also being experimented with and in the longer term could be even more effective.

But self-healing goes far beyond paint.

Self-healing materials: past, present and future

Surprisingly, some self-healing materials have been around since Roman times. They discovered that concrete has some limited self-healing properties: calcium carbonate naturally forms in cracks that appear providing some restorative strength. Scientists today are currently looking at amplifying this effect by adding bacteria to concrete mixture. These bacteria lie dormant until cracks appear which activate them and they then also give off calcium carbonate during their metabolism thus accelerating the re-strengthening process. The UK alone spends £40 billion annually repairing buildings so there are huge cost savings to be had from developing materials that last longer.

The road network is another part of our infrastructure that requires costly repairs. And with roads there is not just the direct cost of repair but also the disruption it causes around our towns and cities. A team in Holland has been given government funding to apply their revolutionary self-healing asphalt technology to a limited section of their road system.

Like concrete asphalt has some natural self-healing property. In hot sunshine, the bitumen starts to melt, filling in cracks, before resetting. Unfortunately this only happens in the summer when the weather is sufficiently warm. That is why the roads degrade so badly each winter. So what is the solution? The Dutch team added shredded steel wool fibres to the asphalt mix. Then, by running induction heating plates over broken asphalt they could get the steel wires to heat up and melt the bitumen in the same way that sunshine would. Their research suggests that this method could double the life of asphalt from seven to fourteen years. Forget the cost savings. If they could halve the number of traffic hold-ups everyone would be happy!

Moving away from these construction and industrial uses, there is really no reason why this kind of technology cannot be applied to any sector. Companies are working on or have developed smartphone screens that fix their own cracks. Car paint that heals scratches in sunlight. And fuel tankers that can withstand bullets without spilling their cargo.

That video was of Bullet Jacket – a spray on protective coating designed to offer protection against small-arms fire. It has three layers: the inner and outer layers stretch around the projectile while the middle layer consists of absorbent beads which swell and turn into a solid when touched by fuel. When applied to fuel tanks in Iraq after the 2003 invasion it was said that one tanker was riddled with over 600 bullet holes, but was still able to carry on delivering fuel.

The future of self-healing is even more amazing

We’ve seen some amazing applications that so clearly deliver massive real world benefits. But what is most exciting about self-healing materials is that they will probably just be a stepping stone to the next – next generation of materials: regenerative or living materials. Self-healing right now is about fixing one specific fault. Regenerative is about fixing entire systems – just like we see in nature.

Working with smart materials? Call ForrestBrown

From piezoelectrics to pH sensitivity, photo mechanicals to Ferro-fluids: if you are working with smart materials in the UK you should make sure you are clued up about R&D Tax credits. They could save you up to one third of your qualifying research and development costs. ForrestBrown wholly specialise in helping limited companies claim this valuable tax incentive, get in touch for a free consultation.

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