Looking for an Unbreakable Breakthrough
Plastics. Strong and versatile, these products are the backbone, heart and lungs of countless devices that make our modern world function. But when these marvels of covalently bonded polymers break, for the most part they're finished. Wouldn't it be great if they could be made self-healing? And wouldn't it be better still if you could repair breaks - even stress fractures too small to be seen with the naked eye - just by shining a light on them?
"That's the eventual project I'm heading toward," says Stephen Ma (Macaulay Honors College at City College, BS in chemical engineering, 2011). Now at the University of Delaware, he hopes to reach that goal through reversible polymer bond structures called covalent adaptable networks (CANs); he'll do that by using thiol-ene chemistry, which mixes sulfur-based compounds with alkenes. (The most famous example of this process is using sulfur to vulcanize rubber, which makes it less sticky, more stable and more elastic.)
Ma will be supported in his doctoral research by a 2012 National Science Foundation Graduate Research Fellowship, the most prestigious award a graduate student in the STEM disciplines (science, technology, engineering and mathematics) can receive. Providing $126,000 over three years, these grants recognize and support exceptional students who have proposed graduate-level research projects in their fields.
For the moment, however, Ma is tackling a related project as he works toward his qualifying exams at Delaware: developing pressure-sensitive adhesives that would be reusable because they're self-cleaning and ultra-strong. In this, he's inspired by a gecko's dry feet, which allow the reptile to climb up glass without leaving a sticky residue. "This project is connected with my self-healing materials project in that I will use the same CANs and thiol-ene chemistry," he says.
This diversity of endeavor reflects the range of research that Ma has undertaken.
As a sophomore at City College, he started doing research with Associate Professor Ilona Kretzschmar and a graduate student, Sonia Mathew, on a project to improve the efficiency of dye-sensitized solar cells.
The next summer he went to Jilin University in Changchun, China, to study Raman spectroscopy of man-sized semiconductor particles. That resulted in a paper published by the Journal of Physical Chemistry Letters; he was the lead author, along with then-doctoral candidate Richard Livingstone (City College PhD in chemistry, 2010), City College chemistry Professor John R. Lombardi and a Chinese professor, Bing Zhao.
That 10-week trip to China was financed by the National Science Foundation's International Research and Education in Engineering initiative, or IREE, and was organized by Purdue University. But he also took separate trips to China and to Japan through Macaulay's Opportunities Fund, which covers the cost of international travel and study.
"My thinking was that as a researcher I'd eventually want to collaborate with scientists from those countries, so it would help to know about their cultures," he says. Ma was born in New York, but his father is from Taiwan and his mother from Hong Kong; he speaks Chinese conversationally, "which allowed me to connect with students while doing research."
Ma is enthusiastic about his undergraduate experience. "The people at the City Honors Program were very helpful in applying for scholarships and fellowships, and the City engineering department is amazing and very open to students doing research. Before I met Doctor Kretzschmar, I had a vague idea of what research was, but she's a terrific mentor, who takes time to talk and give advice."
Macaulay Honors College, he adds, "definitely gave me more opportunities than I could have gotten at any other school, especially the advisement."