On the chemical runway!

Nov 20, 2006

Kettering students are adept in using computer aided design (CAD) resources, but can CAD help them learn more about dynamic interactions and reactions between molecular structures for chemistry?

On this runway, there are no bone-thin, emaciated models prancing back and forth.

No plump red lips painted onto hollowed cheeks and inexplicable pouts. In fact, on this runway, one may find it difficult to even see the "models" at all.

We're talking about molecular models-three-dimensional structures of chemical molecules that comprise every substance in our world.

On the face of it, engineering students at Kettering University don't express a great deal of initial interest when discussing the interaction of chemical molecules. These students are often characterized as entrepreneurial, technologically savvy kids who love challenges. They need to do stuff now. They look at an idea and wonder, "why isn't it smarter, simpler, faster, cleaner or cooler?" In other words, they want to see how systems work. Nevertheless, the reaction and interactions of molecules are not that easy to see with the human eye. And in terms of institutional history, Kettering students like to tinker in automotive labs on vehicle drive trains and hybrid systems, or work on simulating the performance of a bat striking a softball on one of the University's many modeling and simulation programs.

But as the automotive world and other industries begin using newer technologies such as hybrid systems and fuel cell power, the interaction of chemicals on what is described as the nanotechnological scale (one billionth of a meter) in various applications suddenly takes on greater significance.

"Many engineering underclass students are not particularly interested in learning chemical mechanisms during their initial college chemistry classes," explained Dr. Carl L. Aronson of Grand Blanc, Mich., an associate professor of Chemistry and principal investigator (PI) of the Pedagogical Visualization of Polymerization of Reactions Research Project, funded by the National Computational Science Institute and Shodor Education Foundation Inc. of Durham, N.C. "Typically, Kettering engineering students engage in CAD work that deals with the modeling of mechanical parts and assemblies on a meter scale, which quickly builds their visualization skills," he added.

So to help increase interest of undergraduate engineering students in learning about molecular mechanisms examined in Aronson's Chemistry-145: Organic Chemistry course, he began the Pedagogical Visualization research project. As the name suggests, this project utilizes similar graphical techniques and CAD visualization processes used in Kettering's Mechanical Engineering-100: Engineering Graphical Communication to model systems by applying these same resources to molecular modeling.

But as Aronson notes, "the challenge is to get students to see how molecular modeling connects and directly impacts their work as engineers in diverse fields such as the biomedical, microelectronic and automotive industries." Thus, the first step in this project involves engineering students building the two-dimensional molecular structures and minimizing the molecule's energy to determine its equilibrium three-dimensional structure using the computer. The second step involves using the computer to map the region(s) on the molecule that are particularly susceptible to reaction. "This step has preliminarily shown to avoid formulaic thinking and stem the need for routine memorization commonly encountered in the chemistry classroom," Aronson said.

Students subsequently "push" electrons graphically on the computer from one molecule to a particular area on another molecule to simulate a chemical reaction and then determine the chemical product's lowest energy state. Then they follow-up visualization exercises by utilizing their calculus skills in computing the speed of the simulated chemical reaction using a dynamics computer routine developed by Aronson and eight Kettering undergraduate research students. "Using molecular modeling followed by computational kinetics in this manner, engineering students go full circle from initially determining where on a molecule a reaction would most likely take place to simulating the reaction and ultimately controlling the reaction speed and entire production plant," Aronson said. Students can quickly view the effects of changing reactant and solvent identities, concentrations and temperature as well as the effect of impurities much faster than conducting these experiments in the lab to see their effects on polymer molecular weight.

Engineering students then superimpose molecular models onto a CAD mechanical model of their choice, such as a conveyer/gear system, to demonstrate the polymerization chain reactions as a continuous production process merely taking place on the nanometer scale. According to Aronson, "this is how a mechanical engineer might really view a polymerization process." Finally, students "reverse engineer" the problem by superimposing their CAD techniques onto the polymerization chemistry at hand. They draw the molecules as both three-dimensional, space-filled electron density surfaces as well as ball and stick models with the proper bond lengths and angles from the molecular modeling program in the MECH-100 class project.

Aronson takes advantage of the computer and spatial abilities of Kettering engineering students by having them analyze a number of monomers used in the production of automotive plastics on the road today. "Our students are used to tight geometric tolerances in mechanical systems. However, here students are able to 'see' the difference in chemical reactivity as well as the possibility and challenges involved with design of the novel polymeric materials of tomorrow," he said, adding that "molecular modeling tends to cement student learning when interwoven with the hands-on lab approach." Thus, a student's depth of learning regarding the role of molecular structures in the manufacturing and design process will help them as engineers when selecting which chemicals and organic substances to use during the development of a new automobile interior/exterior, for example.

During the current term, Aronson has worked with three Kettering freshmen mechanical engineering majors in Professor Dale Eddy's MECH-100 class on "molecular assemblies" of monomers (starting materials for polymers) as modeled during a polymerization reaction as one part of a class project. These molecular assembly CAD models will undergo rapid prototyping at the end of the term to "create a polymer model from a model polymer," Aronson said.

And while the chemical runway in modeling a molecule is not as sexy as those in New York or Paris, Aronson's project does provide exceptional opportunity for students to visualize the intricacies of chemical systems in a way that makes future engineers even more interested in molecules than ever before. Molecular visualization attempts to close the loop on the first-year engineering experience at Kettering and Aronson hopes that "after performing the exercises within this project, Kettering engineering students will be better able to communicate with chemists."

To learn more about this project, contact Dr. Carl Aronson, associate professor of Chemistry, at (810) 762-9611.

Written by Gary J. Erwin
(810) 762-9538