When materials scientists look at the periodic table
of elements, they don’t see a chart full of symbols and numbers; they see a vast molecular pantry that allows a near-infinite number of recipes. Successful raids on this pantry can benefit all of us. Take solar power. In the 113 years between the discovery of the physics behind photovoltaic solar cells and the year 2000, less than
2 gigawatts of solar power capacity was installed around the world. But recent improvements in the molecular structure of the silicon in photovoltaic panels helped bring online more than 10 gigawatts of new solar power in 2011 alone. Or consider the improvements in desalination plants, where in the past four decades the energy required to turn seawater into clean drinking water has fallen an estimated 90 percent, due largely to improvements in the filters used to remove salts. Cleaner energy and more efficient ways to use it: As the world’s population steadily demands more resources, the ingenuity of materials scientists will become increasingly vital.
To understand the innovations unfolding now—and the ones that may lie ahead—DISCOVER partnered with the Chemical Heritage Foundation in Philadelphia to bring together six experts in materials science. Thomas Connelly is chief innovation officer at DuPont; he has managed the company’s Kevlar and Teflon businesses. Solid-state materials scientist Ryan Dirkx is vice president of R & D at Arkema, where he has worked on Plexiglas acrylic. Global intermediates technology manager at ExxonMobil, Mark Doriski has led production of the molecular building blocks used to create the versatile, chainlike molecules known as polymers. Chemist Greg Nelson is chief technology officer of Eastman Chemical. Chris Pappas is president of Styron, a company that develops plastics, latex, and synthetic rubber. And
A. N. Sreeram, vice president of R & D at Dow’s Advanced Materials Division, works on the application of new materials in the health-care and automotive industries. Ivan Amato, author of Stuff: The Materials the World Is Made Of, moderated their conversation.
HOW IS MATERIALS SCIENCE CHANGING THE WORLD NOW?
A. N. Sreeram: The easy answer is to look at personal electronics. But materials science has made aggressive innovation in other, more fundamental areas that are critically important for us, like shelter. Forty-eight percent of the energy footprint of the U.S. is spent in keeping our living spaces heated during winters and cooled during summertime. We have to conserve that energy. If you insulate your houses well, you can save a lot. Products like polystyrene blue board insulation, along with other materials to seal your windowsills, can substantially reduce leakage of energy from your house.
Chris Pappas: People think of innovation as the creation of brand-new things. But if you take basic molecules and arrange them in the right way, you can do a lot with what already exists. You can apply that to something like an automobile tire: You can change the physical properties of the rubber so that the tire has better rolling capabilities, no loss of wear, and no loss of wet grip. There is a kind of rubber, called solution styrene butadiene rubber, that grips just as well in the rain but doesn’t wear out as quickly. Tires that our partner companies are now working on can improve gas mileage by up to 10 percent, just by changing the tires, because this rubber rolls with less resistance.
Mark Doriski: Along those same lines, we have a synthetic lubricant called SpectraSyn Elite that allows us to improve fuel efficiency both at low temperatures, when you first start up any kind of machinery—for example, an automobile—and also at high temperatures. If you took the whole U.S. automobile fleet, which is more than 200 million cars, and converted one-third of the fleet from conventional lubricant to a synthetic, you could gain 2 percent fuel efficiency. That would save just under a billion gallons of gasoline per year; it’s like taking 1.5 million cars off the road.
Greg Nelson: A clean room [a low-dust, low-microbe environment where computer chips and other electronics are manufactured] is full of devices to push air through filters that scrub it. These applications require that more than 99.97 percent of all particles bigger than 0.3 micron [1/100,000 inch] be removed. That can use a lot of energy. A new technology called microfibers, which is being commercialized right now, allows us to do a higher-performance filtration in many of those systems while saving energy.
Ryan Dirkx: We have a polymer based on vegetable oil that is self-healing. You can cut this material and put it back together,
and it will come back to 100 percent of its original strength in about two or three minutes. [Potential applications for self-healing materials include conveyor belts, shock absorbers, adhesives, paint, and asphalt.]
WHAT ARE THE NEXT BIG CHALLENGES FOR THE CHEMICAL INDUSTRY?
Thomas Connelly: Cars need to get smaller. I believe there is a future for the electric vehicle, but we have to find a way to come up with new materials—for motors, for energy storage, and for inverters, the devices that convert direct current (DC) to alternating current (AC)—and we need to really take weight out. Without those enabling inventions and the materials that allow them, we’re not going to be able to hit the energy goals we’ve set. There is a big challenge there.
Papps: LED lighting is another major materials science issue: diffusing the very energy-efficient light from LEDs through materials that have the right optical properties to provide the kind of light that we need; housing the components in a material that has the right physical properties for impact; addressing wear, non-yellowing, et cetera. led lighting is an emerging technology where materials science is just beginning to play a big role in achieving something for society with lower energy use and energy costs.
Dirkx: Another challenge is waste. When we start designing materials, we should be designing for repurposing, reuse. We would design a material differently if we had in mind the next three or four things it was going to be in its next lives. Take photovoltaic modules. It would be great if in a third or fourth life they could become trash bags.
Nelson: Yes, the grand challenge is to extend the lifetime of a product by making it more durable, and to get more uses out of it by having an end-of-life path. When we take on that challenge, we’ll have plenty of room for the new consumers that are coming up in emerging markets to step into the middle class and become a part of it. If we don’t take on that challenge, it’s going to be a much more difficult world to live in, because there’s not room for everybody to use energy at the rate at which we use it today.
Next Page: What Breakthroughs Lie
Just Around the Corner?