Glass Research Yields Clear Future for Graduate

If you’ve ever seen an artist blowing glass, you likely marveled at the cooling process, as the material goes from a malleable, liquid-like substance into something that is solid and delicate.

This change is known as the glass transition, and it’s at the center of research that Zachery Brown, a graduating senior from Pittsburgh, Pennsylvania, has conducted with Piotr Habdas, Ph.D., associate professor and chair of physics, over the last several years.

“The glass transition occurs in many different materials, not just the silica-based material used in windows and drinking glasses,” Brown explains. “Hard plastics and other polymers, for example, can go through the transition.”

Brown and Habdas’ research focuses on colloidal glasses. A colloid is a mixture of a microscopic, insoluble particles in a liquid; in this case, acrylic spheres in a solvent. Instead of being influenced by temperature, colloidal glasses transition through states based on the ratio of particles to liquid. In Habdas’ lab, using a specialized microscopy technique, Brown measures the movement of the spheres as he introduces them into the solvent.

“As more particles are put into solution, there’s less room for them to disperse,” Brown says. “Eventually they don’t have room to move around, and they start to pack together, approaching the glass transition and mimicking an amorphous solid.” Glasses are called amorphous solids because the particles composing them aren’t arranged in a structured order.

Brown was the lead co-author, with Martin Iwanicki ’16, on a paper covering the research in the international journal “Europhysics Letters,” published by the Institute of Physics in London in November 2016. Habdas and three researchers from the University of Pennsylvania contributed as secondary authors.

“To earn a lead author credit on an academic paper, you must take the lead in all aspects, from research to writing,” Habdas explains. “Zachery took this project from its preliminary stages to the very end. He’s an outstanding independent researcher.”

The glass transition as a phenomenon is still not well understood, according to Habdas, and there is work that needs to be done. But the paper lays out the fundamental framework for future researchers, who could use the knowledge gained at this early stage to make stronger glass materials. It also represents a significant accomplishment for Brown’s resume.

“Undergraduate students don’t regularly get the opportunity to be a lead author on a published paper,” Brown says. “Working with Dr. Habdas has allowed me to get my feet wet and develop the right set of skills before going to graduate school.”

Habdas says that mentoring Brown since he was a freshman gave the student a feel for what being a real, working physicist is like.

“I dropped Zachery in the deep end in his first year and made him learn how to swim,” Habdas recalls. “He has exceeded my every expectation. I’m proud to have worked with him.”

Brown will continue his studies next year at the University of Rochester, where he will pursue a Ph.D. in physics.

“Whether I was conducting research, teaching, or simply studying for my classes, my time in the physics department here at SJU gave me the foundational knowledge I hope to carry with me for the rest of my career,” Brown says.