Sponsored by Procter & Gamble
The physical and chemical processes governing the behavior of complex fluids such as colloidal and polymer solutions result from a delicate balance of weak forces. Although they are subtle in detail, the properties of such "macromolecular" liquids are important in wetting, self-assembly, microfluidic control, and many biological processes. Alice P. Gast has made seminal contributions in understanding these processes and their influence on bulk properties through a combination of colloid science, polymer physics, and statistical mechanics.
Gast, 47, is the Robert T. Haslam Professor of Chemical Engineering and vice president for research and associate provost at Massachusetts Institute of Technology. Her research focuses on a wide range of topics, including macromolecules at interfaces, disorder-order transitions and wetting in colloidal suspensions, magneto-rheological fluids, and microfluidics.
William B. Russel, dean of the graduate school at Princeton University, says of Gast: "Her research program is characterized by her perceptive choice of exciting, but not obvious, problems; exploitation of sophisticated optical microscopy plus light, neutron, and X-ray scattering to probe and visualize structure; effective use of statistical mechanics to model the phenomena of interest; and timely and appealing publication in journals of the highest quality."
"My interest is in systems where the intermolecular forces and interparticle forces are sufficient to cause macroscopic property changes," Gast says. "With submicron-sized particles—nanoparticles, they are called nowadays—there is a lot of surface area, and surface-surface interactions between particles determine macroscopic properties."
Gast says that she has "migrated" during her career from colloidal particles to polymers to lipids and biological molecules that associate into membranes. "Cell membranes and cells are of the same size scale as colloidal particles, and similar forces determine how they will interact," she says. Gast's group is investigating, for example, the unique crystallization properties of proteins tethered to lipid monolayers. In these studies, fluorescence microscopy reveals ordering phenomena of great interest for both biological applications and fundamental physics. Point mutations allow the researchers to alter the protein-protein interactions in a systematic and detailed way and to investigate the molecular basis for the ordering behavior.
"It is a tremendously exciting time in colloid and surface chemistry," Gast says. "We have measurement techniques to measure forces down to piconewtons and smaller, tremendous visualization techniques like atomic force microscopy and fluorescence microscopy, and computational techniques powerful enough to tackle many-body problems. Systems that you study on a computer, you can now actually see in the laboratory. I am tremendously optimistic about the field."
Gast is also deeply involved in policy issues. She is currently cochairing the National Academies Committee on a New Government-University Partnership for Science & Security and serves on the Department of Homeland Security Science & Technology Advisory Committee.
Gast received a bachelor of science degree in chemical engineering from the University of Southern California in 1980 and master's and Ph.D. degrees from Princeton University in 1981 and 1984, respectively. She began her career at Stanford University in 1985, becoming a full professor in 1995. She assumed her current position at MIT in 2001. She has received numerous honors during her career, including election to the National Academy of Engineering in 2001.
The award address will be presented before the Division of Colloid & Surface Chemistry.—Rudy Baum