From Science Fiction to Reality
FSU institute develops materials of the future
Walking through the High-Performance Materials Institute at FSU, a visitor might feel as though he has stepped from reality into a science fiction story. The engineers at HPMI are limited only by their imaginations. They use their advanced computers to create all manner of materials and products for use in industrial equipment, military systems or as consumer products with applications in aerospace, sports and medical devices.
“Imagine going to the beach, and your towel charges your phone. These are the kind of things we are trying to develop at an early stage,” said Dr. Rebekah Sweat.
After receiving her doctorate in industrial engineering at FSU, Sweat worked at the Office of Economic Vitality in Tallahassee for a short time before becoming an assistant professor and principal investigator at the FAMU-FSU College of Engineering in the Department of Industrial and Manufacturing Engineering. She heads many projects at the HPMI, working with doctoral students to produce the materials of the future by innovating products and services with wide-reaching impacts.
One of the primary materials she works with is a carbon fiber composite, which is not very useful on its own.
“It is like a rope. You take a polymer and you stretch it, extrude it through a dye, heat treat it,” Sweat said, explaining the rigorous process required to produce carbon nanotubes.
In creating a useful composite, networks of millimeter-long carbon nanotubes are woven together into networks and aligned into microstructures, which are then treated with an enhancement medium, or unsecured resin, as a load transfer.
This process increases the mechanical properties of the composite material, creating a stronger substance with resins such as polyester or epoxy. The final product is a high-temperature material that can withstand a lot of force and extreme environments, like entering and leaving our atmosphere or withstanding the severe cold and constant radiation of space.
Sweat’s team has discovered — publication pending — that boron nitride nanotubes can withstand temperatures of up to 2,200 degrees Celsius. Applications for this will include heat shields for use in hypersonics or aerospace.
Another area of research at HPMI is triboluminescence in structural health monitoring, where objects emit light when damaged or scratched. This material will be used in prosthetics to determine points of impact. Sci-fi lovers might visualize a multifunctional material capable of determining where structures such as bridges or high-rise buildings and vehicles prone to wear and tear are overstressed or in need of repair.
With a $6 million contract from the Air Force to study the multifunctionality of materials and also given the work it does for NASA, much of HPMI’s focus is on finding military applications, but they also conduct manufacturing and aerospace research for companies such as Northrop Grumman, Solvay and Lockheed Martin.
Teams at HPMI are constantly looking for new applications for their composites, pushing sci-fi closer to reality. Sweat discussed her excitement about the impact these materials could have on consumers at every level of life.
For example, these materials could be used to make clothing that is bulletproof and flame retardant, providing improved levels of safety for first responders.
“Carbon nanotubes are highly conductive and capable of efficient thermal transfer, which will allow us to transform our computing capabilities and reduce energy consumption,” Sweat said. “Shape-memory alloy could be used to manufacture vehicles that cannot be dented. We have the potential to build fireproof homes resistant to damage from hail or extreme weather. Imagine a building with perfect insulation, capable of maintaining ideal temperatures with minimal energy expenditure that lights up when in need of repair.”
Innovative materials from HPMI could make these concepts from science fiction a reality. But, they aren’t quite there yet.
Despite increasing demand for them, composite materials are currently expensive to produce and require extensive experimentation to create useful products and services.
“We are 50 percent making stuff and 50 percent on the computer,” Sweat admitted.
A major first step to getting more technologies into homes is scalability of materials.
“We work with a lot of expensive material, but material costs typically go down over time,” Sweat said. “You will typically see the newest materials in military aircraft, then it trickles down to commercial aircraft and then consumer automotives.”
Beginning with small samples of expensive materials often on loan from companies, they work to scale up production, creating panels or parts. These costly endeavors are mostly performed via simulations with mathematical modeling software.
The institute approaches projects as an engineering design problem first, simulating conditions that would test a proposed material structure before burning up resources in its high-temperature furnace, capable of reaching 2,500 degrees Celsius, or slamming the objects with a ramrod capable of ı0 tons of pressure.
“We want to find out what the optimal configuration or structure is first and match a model to it. Some of these materials can be up to $ı,000 per gram,” Sweat said, “so we try to do virtual design as much as we can.”
Most of HPMI’s work is performed on behalf of businesses and government, but there is some product development on the consumer level. Recently, Dr. Changchun Zeng, professor and chair of engineering at HPMI, developed an auxetic foam. Unlike most substances, auxetic material has a negative Poisson’s ratio, meaning it becomes denser orthogonally in response to an applied force.
In other words, rather than shrinking at the point of impact, this material expands where it is struck, making it ideal padding in sports equipment, as casts and protective braces, or as packing material.
And though our shirts are not bulletproof and phones cannot charge via kinetic energy generated from our pockets, even science fiction writer Philip K. Dick would look at the possibility of these materials with awe and wonder. ▪