More Than Just an Exchange of
Alex Pines and Doug Reimer, chemist and chemical engineer, working together...
Chemistry Professor Douglas Gin and his students may sometimes be found working in Chemical Engineering Professor Jeffrey Reimer's lab. Chemical engineering students in Dean Alex Bell's group are sometimes found working with Chemistry Professor Don Tilley. Professors and students alike are finding that the tools, ideas and methods of the other discipline are helpful, and sometimes necessary, in advancing their research. Chemical engineering is the practical application of chemistry and its fundamental principles within the framework of industry. It increasingly uses the tools of chemists to further research. Similarly, chemists are finding that chemical engineering is necessary to develop new paths for chemistry.
One of the many strengths of the College of Chemistry at UC Berkeley is the collaboration between the Departments of Chemistry and Chemical Engineering. Unique opportunities for research and learning exist here that may be absent from other schools, which typically house chemistry in the college of arts (or letters) and sciences, and chemical engineering in the college of engineering. Berkeley, a preeminent institution in both fields, consistently ranking in the top three programs nationally, is one of three schools in the United States that house them together.
Within the College of Chemistry, the departments share buildings, administrative and technical staff, and in some cases equipment. Students, postdocs and faculty from chemistry and chemical engineering often share ideas and engage one another in their research. Students can have representatives from both departments on their oral exam committees. The fields are, without question, interconnected and interdependent.
Douglas Gin's student, Elizabeth Juang, works with Jeff Reimer on using magnetic fields to order compounds inside nanocrystal structures.
Chemical Engineering Professor John Prausnitz, who is a member of both the National Academy of Sciences and the National Academy of Engineering, says the proximity is key to working together. "We share ideas, and because we are in the same college, there is more congenial reception of ideas than if we were from a different part of campus. If we are not brothers, we are certainly brothers-in-law."
"As chemical engineering became more microscopic in nature, more collaboration followed," says Professor Emeritus Charles Wilke, former chair of the chemical engineering department. "In the early years there were few joint publications. The first serious collaboration I recall was (in the '60s) between Prausnitz and Joel Hildebrand on thermodynamics, which resulted in a landmark textbook on the subject."
Dean Bell, who also served as chemical engineering department chair, agrees. "Over the past 20 years," says Bell, "shared interests have grown as chemical engineering has moved into research at the frontiers of chemistry, and chemistry has moved toward catalysis, biotechnology and materials synthesis."
Bell explains, "Chemists used to make polymers without thinking where they could be used. Today, we make them for very specific, well-defined applications." In his own field of catalysis, there is a definite bridge between the two departments. "The applied side is firmly within engineering," continues Bell, "but the fundamental tools are at the molecular level emanating from chemistry." Chemists determine what constitutes a catalytic site and how to design new catalysts.
Bell and Chemistry Professor Gabor Somorjai have worked together over the past 25 years on surface science, both in the college and as researchers at the Lawrence Berkeley National Laboratory. Somorjai says that the different point of view is useful in chemistry research. "The presence of chemical engineers in my group has enhanced my students' work. Most developments in science are at the boundaries between two disciplines."
Somorjai mentioned petroleum refining as an example in which engineering dominates. In other areas, like in organic material processing, chemistry dominates. But there are linkages within every subfield of chemistry. "In the microelectronics field, where my research has impact," said Somorjai, "a great deal of work is done by the chemical engineers. However, the control is on the nanoscale, so chemistry is very important as well."
Somorjai's reserach with Bell has developed new methods to create thin oxide films on Rhodium.
For example, the construction of disk drive storage devices and other magnetic media, an industry established within the past 15 years, relies heavily on chemical engineering. "These products need very smooth surfaces, less than 20 Å (angstroms) in roughness," said Somorjai. The magnetic recording layer is relatively deep (400 Å) below the surface, covered by protective and lubricating layers. A recording head passes over the surface, and if they touch, scratches can develop. So the technology requires that the surface created be as smooth as possible.
"Chemists and chemical engineers work together in this field to develop surfaces that permit the disk drive to last as long as your computer," says Somorjai, "and since temperature is a factor, to last regardless of whether you live in Alaska or the tropics." Somorjai appreciates that students tend to want to stay close to what they are researching. But collaborative projects expose students to other fields. He says, "Berkeley provides a diversity in the many types of available research. If the students take advantage of it, they are provided a fantastic educational experience." Smiling, he adds, "I make sure my students take advantage of it, whether they like it or not."
Chemistry Professor Alex Pines stresses that while faculty interaction between disciplines is important, "perhaps more important are the relationships among the students and postdocs, sharing ideas. They are the ones doing the work." In recent years, he has worked closely with chemical engineers Clayton Radke, Alex Bell, Arup Chakraborty and Jeff Reimer. He has had several joint students and seminars, and adds, "We are constantly sharing information. The interaction broadens us, giving a real perspective on applications. It is one of the rewarding expressions of the research."
Mathias Haake (left), postdoc in Reimer's lab, with Pines' postdoc Eike Brunner, grad student Lana Kaiser, and postdoc Thomas Meersman.
Students Sharing Ideas
Graduate and postdoctoral students who overlap act as conduits for ideas. Mathias Haake has a Ph.D. in chemistry but did his postdoctorate work here under Reimer in the chemical engineering department. He came to Berkeley from the University of Bonn, interested in Reimer's chemical engineering NMR research, hoping to expand his background. He started out working in catalysis using Nuclear Magnetic Resonance (NMR) but found his research shifting to porous materials, surface dynamics and thin films, no doubt a result of working with the chemical engineers on similar issues.
Haake became interested in studying amorphous surfaces, like a powder, the surface of which is hard to measure. Reimer and Pines have long collaborated on research involving NMR, and Haake worked on ways to improve the technology to use it on porous, amorphous materials. One application of NMR that Pines' group uses involves laser-polarized xenon gas. A laser polarizes, or lines up, the spins of the xenon atoms. The xenon is then introduced to help "light up" signals from the surface, but only for a few milliseconds.
Together, Haake and others in the Reimer and Pines groups worked to create a new technology to introduce a continuous flow of polarized xenon into a sample. The xenon can get into the crevices and pores, thus helping the machine "see" the inner surface of the compound. It can be used to transfer polarization to the surface nuclei, which can, for example, tell the researcher what kinds of carbon molecules make up a carbon-covered surface.
"This new technology is interesting to chemical engineers because it can allow them to observe gas in a constant flow through a structure or a porous system, not just a snapshot," says Haake. "Now, diffusion and flow of the gas can be observed, which was much more difficult before." He adds that an example of interest to chemists would be its use in measuring, with high accuracy, distances inside a biochemical protein or enzyme, specifically within the hydrophobic pocket in a protein.
"Now that I have a much broader background, I can follow chemical engineering issues as well as physical chemistry," says Haake. "Chemical engineering brings physical chemistry and technology together. Research is fruitful when individuals with different backgrounds work together. What we have done here has opened a new playground for technical innovation."
Ron Rulkens is in Chemistry Professor Don Tilley's group, but he does his lab work with Bell. "By matching wits, problems are solved that couldn't be solved before," says Rulkens. "In catalysis, so many factors exist. The way you make and design a catalyst affects its properties." Tilley adds, "Engineers typically use practical criteria to produce a catalyst, using traditional and cost-conscious methods like an industrial research lab would. Chemists use more complicated methods, but don't look at the costs. The two disciplines haven't interacted much, but now we are learning from each other."
Tilley says that interaction demonstrates to his chemistry students practical applications of chemistry, and to engineers unconventional approaches to problems. The two groups are working jointly under a Department of Energy grant to create and study new catalysts.
"Engineering helps us learn which reactions are the most important to catalyze," said Tilley. Rulkens adds that one consequence of this interaction is the additional meetings he must attend, "but the experimentation resulting from them is more effective."
"It is easy to say the other's approach isn't relevant," said Tilley, "but in keeping an open mind, we learn more about chemistry. Our results have improved after collaboration." Tilley, a Berkeley Ph.D., came to the Berkeley faculty from UC San Diego, where he said he had less contact with chemical engineers. "Here, the engineering has a chemical flair. Rather than just process design, they are interested in fundamental issues of chemistry. Chemical engineering students come to me and ask how to make catalysts. That wouldn't happen as easily if the departments weren't housed together."
New Applications Through Collaboration
Professor Gin began talking with the chemical engineering staff here during his job interview, seeking out collaborative efforts quite early in his career at Berkeley. He currently has a joint graduate student with Chemical Engineering Professor Jeff Reimer. Elizabeth Juang is examining new nanostructured materials made in the Gin group using NMR techniques and equipment developed in the Reimer group. The organic materials that Gin and Juang have created are insoluble once assembled into polymers, making it difficult to probe the structure using normal methods available to organic chemists. So they turned to the chemical engineers for assistance.
The chemical engineering applications involve probing the structure and environment inside the materials that Gin and his group have recently developed. These materials are polymerized surfactant assemblies that contain uniform arrays of hexagonally packed water channels, like a honeycomb. The diameters of these channels are measured in nanometers. New compounds and materials can be created inside them because they afford a very unique environment for synthesis. This artificial environment affords different properties than if the compounds were constructed normally in bulk.
An electron microscope picks up the honeycomb shape of the channels that have been created (see illustration below photo) in Gin's research. The channels will be used to create new types of materials.
Juang is working with Reimer using solid-state NMR spectroscopy to probe the environmment inside these nanometer scale channels. In addition, she is also using strong magnetic fields to order the liquid crystal assemblies macroscopically in different ways, which is bringing some aspects of engineering into the chemistry.
Gin says these structures have demonstrated several uses, such as heterogeneous catalysts in organic reactions, and ordered matrices that often enhance the properties of the fillers grown inside the channels. One of the nanocomposites that Gin and his group have recently developed contains light-emitting polymers inside. "With performance and property enhancement, this could be developed into a new light-emitting display," says Gin. He emphasizes the need for collaboration with chemical engineers. "To get to the next level, we need engineering to make something useful. It is crucial to my agenda to have materials science people working with the new materials we create," says Gin.
"It really helped when we saw this interaction can work. Now, Reimer, (Chemical Engineering Professor Susan) Muller and I are working on a NSF grant for further collaboration," said Gin. If awarded, they will continue researching these peculiar molecules. An outside company will be hired to make kilos of the compounds for research. Muller will work on the methods for processing the compound. Reimer will work on solid-state studies (structures) and magnetic alignment, and Gin will work to develop new applications and new chemistry.
"In this case, things are ordered on a very small scale. Chemical engineering gives us insight on the effectiveness of the chemistry, through optimizing processing and bulk structures," says Gin. "We are trying to control the order to enhance properties on the small scale. Engineering takes us to the other end of the spectrum, a useful technology."
Present and Future
Another first at Berkeley was the dual appointment for Professor Arup Chakraborty, a chemical engineer, recently added to the Department of Chemistry faculty as well. Graduate students and postdocs from both disciplines are brought together in Chakraborty's group. "Each department has a slightly different character, a different language. Students in my group get to see both cultures," he says.
"It was precisely the right time in these two fields to have a joint appointment," says Chakraborty. "We are in the 'Silicon and Plastic Age.' Tools and theories at the cutting edge of fundamental science are now being used to unravel the behavior of these complex materials of industrial importance," he says. The study of these complex materials provides opportunities for doing both good science and good engineering. "Some of the phenomena that we have observed in our laboratory have elucidated issues pertinent to many-body phenomena. The possibility of exploiting these phenomena in applications makes my work of relevance to engineering," says Chakraborty.
He continues, "I feel that the impact that my theoretical work has had on the engineering or applied community is largely due to the dynamic intellectual climate provided me by some of the world's best theoretical chemists in our College: (David) Chandler, (William) Miller, Martin Head-Gordon, and (Robert) Harris."
Current Chemical Engineering Department Chair Harvey Blanch says that funding links between the disciplines have been increasing, but they have been around for years. LBNL has long had advanced materials teams combining chemists and chemical engineers on research. He himself has worked on joint biotechnology grants with Jack Kirsch and Peter Schultz from Chemistry. Currently, a joint training grant is shared by biochemists and engineers, supporting students with stipends and tuition.
"Chemistry is the core science. We build from that to develop processes and products. Engineers are more interested in synthesizing products, systems," says Blanch. Because chemists typically don't have as much math or physics in their background, he says, "It might be more difficult for chemists to learn and apply engineering skills than for an engineer to apply chemistry skills." But there are examples of crossovers. Chemical engineering undergraduates occasionally end up going on to teach chemistry, as did Somorjai, John Hearst and alumnus Sunney Chan (B.S. ChE '57, Ph.D. '61 Chem, now a professor at Cal-tech). Some go the other way as well, as did Chemical Engineering Professors Jay Keasling and Doug Clark, whose backgrounds are in chemistry.
When asked where students end up, Blanch said, "More often, chemical engineers go into chemistry-based technology industries--semiconductors, biotech--less often in the chemistry and petrochemical industries than in previous years."
New students in the college have a very flexible program at their disposal, says Associate Dean for Undergraduate Affairs Herbert L. Strauss. "Students don't have to declare a major until their sophomore year," he says, "and can switch back and forth between chemistry and chemical engineering fairly easily." Fall seminars for freshmen expose them to both disciplines, and both curricula allow the exploration of the other field. Chemical engineering also offers a double major with materials science or nuclear engineering. Many chemical engineering students want a B.S. and then a job, while most chemistry students generally go on to graduate school. So Strauss says it depends on a student's personal goals which program is better. "Right now the chemical engineering job market is doing well. It is a good time to be an engineer."
The future of both chemistry and chemical engineering, says Professor Chakraborty, will include increased levels of collaboration. "The world does not make money from commodity products anymore. We need technology with precise properties, requiring molecular engineering. Chemists want to apply their research more. The boundaries between the fields have been confused."
Berkeley is at the forefront of research in both fields, and the unique opportunities for collaboration between the departments here will contribute to that leadership.