AMHERST, Mass. -- A University of Massachusetts professor has found a way to endow surfaces with precise qualities, such as their degrees of polarity or water absorption and all on a molecular scale. The research, by polymer scientist Thomas P. Russell, is detailed in the March 7 issue of Science. The implications of Russell¹s work are far-reaching, potentially affecting fields as diverse as microelectronics and medicine. This is Russell¹s third article in the prestigious journal.
"We can make a surface to someone¹s specifications; whether that surface does or doesn¹t like water, or does or doesn¹t like bio-active material," says Russell. "You can have black, white, or any shade of gray. We can offer extreme precision."
Surfaces can be customized to any degree of absorbency, adhesiveness, bio-activity, or electronic charge, for instance. In medicine, the work could help create fine-tuned time-release pharmaceuticals, build molecular scaffolds on which to grow tissue, or provide coatings on surgical implants made of materials that would otherwise prove toxic to human beings. The research also has potential use in activities as serious as oil recovery and microelectronics, (where it can be used to create channels of conductivity and insulation), as well as in products as nonscientific as house paint.
Russell and his colleagues manipulate surface qualities by working with a long chain of molecules known as polymers. The scientists place thin films on silicon foundations, which scientists call "substrates." Then they graft polymers to the substrate by soaking the films in a chemical solution, heating it, and rinsing it with a solvent, says Russell, who uses long strings of beads -- representing monomers and polymers -- to explain how chains of molecules behave. The attached polymers are called co-polymers.
"We can change the composition of a surface with the precision of turning a knob," says Russell. "And you can make changes in the co-polymers -- you can add more Œbeads¹ when and if you want to -- giving scientists enormous flexibility."
While scientists have already manipulated co-polymers in order to change surfaces, previous methods for doing so were unwieldy and inexact.
"In terms of industrial applications, the simplicity is very important," says Russell. "We¹re working with nature, to help nature do what we want it to, and when we want. We can take a surface and change it, and change it the way we wish."
Russell is a new member of the University faculty, having arrived on campus last August. Previous to his University appointment, he spent 15 years as a research scientist for IBM. He received his doctorate in polymer science from the University in 1979. His colleagues on the project were Paul Mansky, a post-doctoral fellow; Elbert Huang, a graduate student; and Craig Hawker, a research staff member at the IBM Almaden Research Center.