When Andre Geim and Konstantin Novoselov first isolated graphene in 2004, they knew they were onto something big.
The researchers had taken a chunk of graphite — the main material used to make a pencil lead — and carefully used Scotch tape to peel back its layers little by little. What they found was that the structure of graphene was a single layer of carbon arranged in an interlocking pattern.
Their discovery of the carbon-based nanomaterial earned them the Nobel Prize in Physics and sparked a burning question among scientists — how is graphene so strong yet pliable? And how could we harness its unique properties to make flexible electronics?
Like diamond, graphite and coal, graphene is an allotrope of carbon. Allotropes are different substances made from the same element.
Although they look and behave very differently, on a molecular level, the only difference between diamonds and coal is how their atoms are arranged. Diamond is made from a 3D lattice of carbon atoms that each bond to four other atoms. Coal looks like a hectic tangle of balled-up chicken wire.
What makes the molecular structure of graphene unique is that it’s just a flat sheet. Graphene effectively lacks a third dimension, making it the thinnest two-dimensional material in the world. With a thickness of only one atom, graphene is a million times thinner than a strand of human hair.
The molecular structure of graphene is tessellated. That means the carbon atoms are arranged in an interlocking pattern — in this case, hexagons — just like chicken wire or honeycomb. Carbon-carbon bonds are unusually strong, and a hexagonal array distributes stress evenly across its structure. These attributes make graphene the world’s toughest known material, a staggering 200 times stronger than steel.
Despite its strength, the atom-thin structure of graphene also makes the material incredibly flexible. It’s lighter than paper and has a higher thermal conductivity — the ability to conduct heat — than copper.
Graphene is also an excellent conductor of electricity and has a quick response time. One day, it might replace silicon as a semiconductor inside computer chips.
Graphene’s conductivity and bendability make it a strong contender for building flexible electronics. What are the most promising use cases for this so-called supermaterial?
You can print graphene-based ink on a standard printing press to create circuits on fabric. When printed on waterproof cloth, these circuits can be washed, twisted, heated, ironed, dried and wrinkled without damaging the flexible electronics inside. Perhaps lasers or die-cutting machines could cut graphene fabric into extremely precise shapes to make clothing, furniture or bedding.
Fabric-based flexible electronics have countless potential applications. You could make ultra-thin filters or more comfortable, responsive prosthetic limbs. Graphene shoe inserts could track people’s steps or monitor pressure inside shoes for podiatry purposes. Perhaps flexible electronic sheets could be used in pressure mapping across a person’s entire back to prevent bedsores. Wearable patches attached to the skin could measure people’s heart rate, blood oxygen and levels of UV exposure from the sun.
Right now, soft epidermal sensors with adhesive backing — such as the kind used to diagnose and treat jet lag, sleep disorders and pressure ulcers — are the most advanced battery-free skin sensors available. However, they tend to only measure one thing at a time at a particular location on the body. Flexible electronic fabric could be used to create full-body suits for more comprehensive measurements.
Electronic fabric would be a game changer for making heated or refrigerated clothing. Battery-powered temperature control clothing already exists, but it’s very heavy due to the large batteries required to power it. Imagine paramedics being able to rapidly cool down heat stroke victims with a cold blanket or construction workers having heated suits for working outdoors in the winter.
Because graphene is so thin, it’s possible to spray it onto or mix it with other materials to make it stronger.
For example, you can combine graphene and chopped-up rubber in a machine to create a flexible material with higher strength and temperature capabilities than rubber alone. Going from extremely high to low temperatures — such as in space — causes the rubber to expand and contract, which can make it crack or lose strength over time. Mixing it with graphene would combine the best attributes of both materials.
Mixing graphene with metal is called making an alloy. Graphene could reinforce pure metals like aluminium or titanium to create stronger materials for the aerospace industry.
A sheet of graphene is almost completely transparent, making it a strong contender for a new type of bendable phone or computer screen. This technology would allow you to drop your phone without it shattering. You could also roll your computer up and stuff it into your pocket, and it would conform to the shape of your body.
Bendable phones are probably still a ways off, but graphene touchscreens already exist. Researchers invented the first one in 2010 and will hopefully expand the technology to consumer products in the coming years.
Picture a future in which contact lenses could help you see in the dark or protect your eyes against electromagnetic waves that could cause cataracts. Imagine a world in which skin-integrated sensors warn you when you’re dehydrated or have low blood sugar.
Flexible electronics would enable more than just new kinds of fabric — they would allow engineers to create medical devices that work directly with the human body. This is one of the most exciting prospects of graphene. It could give people with chronic conditions much more control over their health, enabling them to lead more fulfilling lives.
There’s a lot of hype around graphene right now, and for good reason. The material has so many applications that it’s hard to keep count, with the most promising ones being flexible electronic fabrics, bendable screens, strong new alloys and wearable technology. In the coming decades, it may be possible to fly flags with computer screens on them or wear medical devices directly on your skin. Graphene may be atom-thin, but make no mistake — there’s a lot more to it than meets the eye.