May 19, 1998
Voila!
Chemistry Students At DePaul University Are Cooking Up
Polymers New to Science
Voila!
Chemistry Students At DePaul University Are Cooking Up
Polymers New to Science
Organic Chemistry. It’s a college lab course that sends shivers down the spines of even the bravest pre-med students. But at DePaul University, it is a class students can’t wait to take. That’s because during spring quarter students know they get to invent their own polymer – one that may never have seen the light of a laboratory before.
For five years, Gregory Kharas, an associate professor of chemistry, has helped sophomore students see the fun side of organic chemistry by assigning each of them an unknown polymer to create in the lab. A polymer is a large molecule formed when smaller molecules are linked together in chains. Synthetic polymers include plastics, rubber, and paint. The search for new polymers is a major focus in the field of materials science, where discoveries can lead to breakthroughs in medicine and technology.
"They come running into my office shouting ‘I got it!’" said Kharas. "There’s no greater thrill for a teacher than to see the kind of confidence that scientific discovery can bring."
Kharas’s students have been so successful at discovering new polymers that for several years they have been invited to present their projects at the annual meeting of the American Chemical Society. Students also have been listed as authors on research papers published in scientific journals – an honor usually reserved for professors and graduate students.
For the past three years, the course has been funded by a $70,000 grant from the National Science Foundation. It has gained so much academic attention that Kharas was asked to write a paper describing his course in the "Journal of Chemical Education."
A bespectacled, fatherly figure with a broad smile and a twinkle in his eye, Kharas walks the halls of the science building at DePaul and waves to several of his students. He points proudly at posters on the wall, filled with pictures of past labs in action. Kharas keeps a camera in his office and takes pictures of students as they work, surprising them as they bend over test tubes with heavy goggles obscuring their eyes. Each photo has a humorous caption below it, written by the students themselves.
"See how much fun we have?" said Kharas. "They really enjoy their time in the lab."
When Kharas was laid off from his job as a researcher for a chemical company six years ago, he attracted job offers in both research and teaching. He chose to change his career. As a teacher, he thought he could have the best of both worlds by bringing the excitement of research to undergraduate students.
"In science, when you make a sudden discovery, it can be a spiritual experience," said Kharas. "Self-discovery and discovery in science are very closely related. I wanted students to experience that. It builds confidence and takes some of the fear out of going into science as a career."
Some students who had not planned to pursue a chemistry career changed their minors to chemistry after taking his course, which is filled to capacity this year with 50 students. In addition, DePaul has about 45 students majoring in chemistry.
"Dr. Kharas is an invigorating teacher," said Jay Kropp, a senior at DePaul planning to go to medical school. "His class was like no other I have ever taken. His curiosity and the wild-eyed look he gets when you talk about the project really inspired me to work hard."
During the fall and winter semesters, Kharas’s organic chemistry lab is much like any other. Students do textbook experiments and learn about the relationship between compounds and the reactions in which they play a role. Kharas lets his students know from the very beginning of class that all of this tedious "practice" work will pay off in the spring, when they get to try creating a polymer of their own.
"The usual organic chemistry textbook is like a cookbook," said Kharas. "Students follow each experiment the way it’s spelled out in the book, and then compare their results. It’s like making a cake. But the question is, how many different cakes can you make?"
Kharas scans the literature within a certain family of chemicals to find single molecules, or monomers, that are largely unknown to science. They go by such complicated names as methyl 2-cyano-3-(2,4,6-trimethoxyphenyl)-2-propenoate. "What I do know about them," said Kharas, "is that they’re not really toxic or explosive."
He then assigns one monomer to each student. The first part of their project takes place in the library, where they learn how to do a literature search to determine if any studies have been done on that compound – and whether it’s been produced before. If they find something, they are assigned a new compound. "Of the 200 compounds we’ve assigned in this course so far, only three percent were in the literature," said Kharas.
The students then move into the lab to attempt to produce their monomer through experiments. "Some find that the monomer itself can’t be made," said Kharas. "In that case, we assign them a new one." If successful, the students take their monomer to the next level by trying to make it into a polymer.
"They don’t know what kind of polymer they’re making, so the result is always a surprise," said Kharas.
At the end of the semester, each student submits a feasibility report on their compound with samples attached. Volunteers and graduate students have taken some of the most successful projects to the next level by doing analyses and publishing scientific papers on them. Two papers covering the results of 93 projects have been published in the "Journal of Macromolecular Science."
In Kharas’s laboratory, shallow boxes filled with neat rows of small test tubes holding white and yellow powders are labeled by year. These are the monomers and polymers of past students, the raw materials of scientific discovery.
Not everyone is successful at making a polymer. Some of the monomers simply aren’t reactive enough. But Kharas stresses to his students that this is also an important part of scientific research.
Kropp can attest to that. His polymer never materialized. "Although I was disappointed at the time, I can see now that the other side of the project was eliminating the compounds that wouldn’t form a polymer," said Kropp. "I realized that I was an important participant in this process, and that it was something worth knowing."