Five materials that changed the world

Stone

Early man roamed a brutal and unforgiving wilderness that would have quite literally eaten him alive if he didn’t make use of what nature handed him. Stone was the first material to be successfully fashioned into tools, weapons and shelters.

“Stone is the critical material that allowed the earliest humans to develop weapons to protect themselves, to kill for food, and in those days that was obviously important for survival,” says Doug Perovic, a professor in the department of Materials Science and Engineering at the University of Toronto.

Wood

As all children know, sticks are an important companion to stones – and no more so than in early times, for vital tasks such as breaking the bones of enemies and gathering food.

“Wherever wood is available — which of course is not everywhere — we notice human beings tend to use it to the maximum, because it's enormously versatile, and it's also very easy to work, unlike most other materials,” says Robert Friedel, a history professor at the University of Maryland, adding that wood also provided early civilizations with access to tools, habitation, infrastructure and transportation such as ships.

Bronze

Long before it came to symbolize being an also-ran in Olympic tournaments, bronze was first engineered in the fifth millennium B.C. by combining core elements: initially copper and arsenic, and then copper and tin. The Bronze Age, which got its start in in the ancient civilizations of Sumer and Mesopotamia, stands out as a turning point in human development because it was the first time two naturally occurring materials had been combined to create something new, Prof. Perovic explains.

“It's with the advent of processing, which then became engineering in the more generic sense, that things really started to change,” he says. “The Bronze Age is where they started to heat things up and doing metallurgy and started making alloys.”

Steel

Once we figured out that heating up metals and mixing them together created new and exciting stuff, a world of possibilities opened. Although iron and primitive forms of steel had been around for millennia, it was improvements in the steel smelting process in the 19th century that kicked things up a notch.

“If you were going to pick one of the key drivers for the industrial revolution in the 1800s, that was the ability to create iron,” says Prof. Perovic. “Steel came from that, which is much more useful than iron, then you can make all these kinds of steel — hard, tough, stainless and so on — so that was a huge point of change in our civilization, driven by materials technology.”

The discovery of steel drove the industrial revolution, mass transportation, assembly lines, skyscrapers and other key aspects of modern life.

Silicon

It’s given us far more than the name of an overpriced valley in California. When anthropologists look back on the current era, the material that will stand out as the most significant, according to Prof. Perovic, is silicon. The element, and the versions of it used in electronics, is at the bedrock of the technological revolution that has transformed modern life.

“Students ask me, 'we had the Stone Age, we had the Bronze Age, we had the Iron Age, what's the age after that going to be called?’,” he says. “A lot of the chemists and so on will call it the Plastics Age, but there's no question that it's going to be the Silicon Age.”

...and five for the future.

Nanomaterials

Just as heating and mixing elements opened the floodgates of innovation, so too will the process of manipulating their molecules on a nanoscale. Nanomaterials are already being used to perform many futuristic tasks, including personalized nanopharmaceuticals; for example, gold nanoparticles can be used in cancer therapy as a targeted antibody transportation device, while nanoparticles of silver have proven antibacterial properties and also show promise delivering targeted chemotherapy.

One of the most promising new nanostructures, carbon nanotubes, may have applications in medicine, electronics, environmental cleanup and battery storage, among other things.

Which brings us to …

Graphene

Graphene is a nanomaterial that is getting so much buzz as a game-changing invention that it’s worth its own item. It’s a layer of carbon so thin – one atom thin, in fact – that it is referred to as a 2-D material. Stack the layers on top of each other and you have one of the lightest yet strongest material man has devised. It is 200 times stronger than steel and one million times thinner than a human hair.

“You take graphite, like your pencil, and you can strip off, using sticky tape, a single atomic layer. That's how it was first done,” says Prof. Perovic, referring to its discovery in 2004 by researchers at Manchester University in the U.K.

Graphene’s likely applications include better storage in batteries and for wind and solar power; semiconductors and computer chips that outperform silicon; an additive in composite materials; biosensors and drug delivery inside the body; membranes for desalination and water filtration; and as a material in consumer products such as bendable smartphone screens.

Graphenemania has become so widespread that international conferences are devoted to its potential and governments are pouring millions into R and D.

Organic materials

Organic electronics attempts to recreate electronic processes using the sophisticated functions of organic (i.e. carbon-based) materials. It works by harnessing properties such as conductivity that are present in organic molecules and polymers to create the next generation of electronic devices; for example, light emitting diodes, solar panels, thin film transistors , sensors, memories and more. Using these materials, scientists have been able to manipulate DNA to act as a memory device and create flexible, organic LED display screens.

So why use organic compounds over metals and other inorganic materials? For one thing, they are proven to work: The human brain, which is among the best computers on earth, is entirely made from organic material.

Researchers also hope production will be much cheaper and the new materials will be more flexible and adaptable. Then there is the DNA advantage.

"Having DNA computing is really where the future is. DNA as a memory device can store things for thousands of years, we know that from biology, so to actually program and use DNA for information technology, for computation, that's all being done," says Prof. Perovic.

Self-healing materials

Realizing how elegantly our bodies repair themselves while inanimate objects don’t, researchers are now trying to mimic that healing process in materials.

For example: By embedding a self-activating, limestone-producing bacteria into concrete, researchers have given the substance the ability to heal itself, much like human skin. Researchers at MIT have also discovered a mechanism that can close cracks in alloy metals under stress. Such materials have immense implications for reducing the environmental footprint of building materials, not to mention repair costs. “Imagine denting your bumper, and when you look again in the morning the car's fixed itself. I'd like that,” says Prof. Perovic.

Solar fuels

Most machinery in the modern world runs on fossil fuels and emits carbon dioxide, while complex systems in nature consume CO2 and emit clean air. Engineers are currently in the process of creating what amounts to an artificial leaf − an energy source that sucks up pollutants and emits clean oxygen.

The goal of solar fuels is to store the energy of the sun in liquid form that is compatible with today's energy infrastructure. For example, imagine powering cars, generators, jets and homes with a liquid energy source that uses nothing but the sun and photosynthesis. Researchers are working to replace our dependence on oil and gas with an environmentally friendly solution. New Mexico-based Joule Unlimited, for example, can now convert waste C02 into ethanol or hydrocarbons for diesel, jet fuel and gasoline.

“All the oxygen we breathe on the planet is a product of photosynthesis, so we can mimic that and produce materials that can create fuels,” says Prof. Perovic. “We now have that engineering problem of making it technologically feasible and economically attractive, but it's great because you'd be killing two birds with one stone: Sucking up C02 instead of making it, so helping solve the climate change problem, and at the same time you've got a new source of energy that's completely green.”