Chemical engineers have found a way to group molecules so tightly that they form a slick surface useful for a multitude of medical, technical and industrial applications. The research, supported by the National Science Foundation (NSF), is reported in the December 15 issue of Science.
Jan Genzer and Kirill Efimenko of North Carolina State University have forced molecules to create an almost impenetrable layer by bonding them chemically to a polymer material that has been stretched, then released again to regain its original shape. The molecules are jammed into a tight-knit, non-stick layer that could one day coat everything from frying pans to disk drives, medical implants to airplanes. Such surfaces would be highly water-repellent and nearly frictionless, and might reduce the need for many lubricants.
"This was a very clever way to pack molecules more closely than nature intended," said Andrew Lovinger, NSF's program manager for polymers. "While much research has gone into synthesizing new non-stick materials, Genzer's technique is the only one that can improve the surface of any of these materials by squeezing their molecules tightly together."
Lovinger says potential applications from this finding include: improving the biocompatibility of medical implants or prostheses by reducing friction and inhibiting the interaction with surrounding cells; coating airplanes with a water repellent that could eliminate the need for de-icing; and covering adjacent disk drive components with a substance slippery enough to prevent scratching.
So far, the researchers have worked with a nano-sized layer of fluorinated molecules, bonded to an elastic polymer similar to silicone rubber. Fluorinated materials are the common ingredient in the polymer surface of products such as non-stick cookware, water-repellent fabrics, and self-lubricating engine parts. Next, the team will experiment with lower-cost hydrocarbons.
"By manipulating materials at the nanoscale, we can vastly improve on what Mother Nature offers, for the benefit of both manufacturers and consumers," said Genzer.
NSF supports Genzer's work through a CAREER award. These five-year awards are designed to offer young investigators an initial source of support for developing innovative research ideas and integrating them into their educational activities.
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