Strength in Nanoscience
By Melinda Martinez
(from left) Jeffrey Alston, Ph.D. (Principal Investigator), Haley Harrison (Ph.D. candidate), Reginald Goodwin (Ph.D. student), Bolaji Sadiku (Ph.D. student), James Knoop (Ph.D. student), Spencer Twiddy (research assistant), Sam Huneycutt (research assistant). Photo taken before COVID-19 restrictions.
Jeffrey Alston, Ph.D., studies the interface of nanoparticles, to improve their properties to make different materials compatible. Those goals also apply to his team.
His students come from various disciplines and backgrounds. Alston teaches them to utilize their discipline-specific individual skills while also training them in a common language of nanotechnology, so that they can interface with others of different backgrounds to improve their research and learn from each other.
In his lab at North Carolina A&T State University and the University of North Carolina at Greensboro’s Joint School for Nanoscience and Nanoengineering, Alston and his students create new materials by manipulating surface chemistry and functionalization for incredible applications of high strength and low-density materials for aerospace applications and beyond.
“The theme of our group is training the next generation of nanoscientists and nanoengineers. I convey to my students that invention and creativity in nanotechnology stems from the collaboration of many disciplines coming together to see the bigger picture while understanding the phenomena at the smallest scales,” Alston explains.
In 2019, Alston received a Minority Serving Institution Collaborative Research Grant from NC Space Grant to support interdisciplinary faculty-student research in collaboration with NASA. The funding was an effort to increase the number of underrepresented scientists and engineers developing next-generation materials for the aerospace industry.
“The future of space exploration — from spacecraft to spacesuits — is dependent upon nanotechnology. Providing opportunities for the future workforce to engage in cutting-edge research like nanotechnology is the primary mission of NC Space Grant,” explains Jobi Cook, NC Space Grant associate director.
This program supports NC Space Grant’s commitment to building inclusive research, education and public outreach programs that engage diverse populations.
Haley Harrison is the primary Ph.D. student for this project and is focusing her research on boron nitride nanomaterials. Now in her fourth year, with plans to finish her dissertation in Summer 2021, Harrison became interested in the nanotechnology world as an undergraduate while learning about electron microscopy in physics class.
“I thought it was so cool that you could make these tiny structures and they’re all perfectly oriented to get little diamond shapes,” Harrison explains.
The team also includes six of Haley’s graduate peers and four undergraduates working on related projects to explore chemistry and testing methods. The students come from various backgrounds, including environmental chemistry, petroleum engineering, mechanical engineering, as well as physics and chemistry. That combination brings many perspectives — and creative thinking.
What is Nanotechnology?
Nanoscience and nanoengineering create nanotechnology — this involves using properties of extremely small materials and make them usable for a wider range of applications. Nanotechnology is used across many fields, including biology, chemistry, physics, engineering and medicine.
Alston and his team perform controlled stoichiometric chemistry on the surface of nanoparticles. In other words, they use chemistry to break and form molecular bonds — and hopefully create new, compatible nanoparticle surfaces to increase functional properties.
Alston’s NC Space Grant-supported project focuses on using boron nitride nanomaterial. Boron nitride can exhibit similar structures as carbon, such as forming graphite, graphene and nanotubes. Boron nitride structures then can mirror those same mechanical properties, while also increasing some physical properties.
Harrison works with highly porous nanomaterials called aerogels, which are mostly made of holes. An aerogel looks like a translucent block of material that can be used to build amazing things — but what you see is only about 10 percent solid matter. The holes make the material almost as light as air and increase the surface area of the materials, which is important when changing surface properties — but all those holes can also make the material fragile.
Harrison and Alston are exploring chemistry that allows nanomaterials to become part of the aerogels and make them stronger while maintaining the low-density of the aerogel. Boron nitride nanomaterials can be stronger than steel, becoming almost as hard as diamond. They also have very high heat conductivity, low electrical conductivity and absorb radiation. These properties make it a great candidate for structural composites, heat transfer and radiation-shielding material — ideal for space applications.
Challenges with Boron Nitride
Boron nitride has enormous potential for many applications; however, it cannot stand on its own for every use.
“There’s no carbon, so it is thermally and oxidatively stable to about 800˚C, as opposed to carbon which starts to oxidize and chemically react at about 400˚C,” Alston explains, adding that boron nitride materials would be very good for thermal and oxidative environments, but for the same reasons are much more difficult to chemically functionalize than carbon nanomaterials.
One of the main issues with the use of boron nitride, and many other nanomaterials in general, is dispersing them well into other materials.
“Creating nanomaterials can be similar to baking, where you mix various ingredients to create something new. Except with nanomaterials, unless we put them through a chemical process or wrap them with something else, it’s more difficult to disperse them well. That’s a characteristic of all nanomaterials, they like to stick to themselves,” Harrison notes.
“So, we’re focusing on how to make the boron nitride not stick together, so that we can spread it out into the original liquid solution, so when we’re done, we have materials with improved properties instead of limited properties and poor performance,” she adds.
“They’re effectively ceramic-type materials, so if you could reinforce a polymer material, you could create composites that would be able to be used in unfriendly environments, such as space or at high temperatures, and still provide some structural stability,” Alston explains.
In space, astronauts and technology need protection from the sun’s radiation, which can penetrate the skin and increase the risk of cancer. Radiation is energy from the sun and comes in the form of electromagnetic waves. On Earth, we are protected by a magnetic bubble, but beyond Earth, humans and materials need protection.
The new project fits well in the scope of Alston’s lab.
“Our interest is trying to translate nanoscale properties into bulk materials — and make them compatible with whatever that material is,” Alston explains. “So, it is important to understand the chemistry and know how to control it. Essentially, we are breaking nanoscale surface chemistry apart, to disperse the particles well, and then attaching them to polymer backbones with compatible chemical linkers,” he says.
Restrictions associated with COVID-19 have halted some of the students’ research work by prolonging the wait time for the batch testing they rely on at NASA labs. The team also had to cancel planned hands-on training with NASA Glenn Research Center scientists. Lab group meetings continue virtually, but lab testing even at the NC A&T campus halted, leaving some students in limbo.
Fortunately, Harrison was able to visit NASA Glenn in Ohio for hands-on training before COVID-19. She began the process for testing in the lab and patiently waits for NASA experts to access labs to finish processing her aerogels.
The NC Space Grant funding was a great opportunity for Harrison to work directly with NASA and utilize their lab space. In fact, with that connection, Stephanie Vivod, a chemical engineer at NASA Glenn, is now a mentor and serves on Harrison’s doctoral committee.
Harrison hopes to continue to work with NASA and feels this funding has opened doors of opportunities in the future. “After my dissertation, I hope to intern and eventually work at NASA, and I feel like this could be possible because of NC Space Grant,” she explains.