New, Invisible Nann-Fibres Conduct Electricity, Repel Dirt

Tiny plastic fibres could be the key to some diverse technologies in the future-including self-cleaning surfaces, transparent electronics, and biomedical tools that manipulate strands of DNA. The patent-pending technology from Ohio State University involves a method for growing a bed of fibres of a specific length, and using chemical treatments to tailor the fibres' properties. For this study, the scientists grew fibers of different heights and diameters, and were able to modify the fibers' molecular structures by exposing them to different chemicals. They devised one treatment that made the fibres attract water, and another that made the fibres repel water. They found they could also make the suiTaces attract or repel oil. Depending on what polymer they start with, the fibres can also be made to conduct electricity. It was also found that the attracting surface does the same thing to coiled-up strands of DNA. When they put droplets of water containing DNA on the fibers, the strands uncoiled and hung suspended from the fibers like clothes lines. Depending on the choice of polymer, the nano-fiber surface can also conduct electricity. The researchers were able to use the surface to charge an organic light-emitting device-a find that could pave the way for transparent plastic electronics. Since dirt, water, and oil don't stick to the repellent fibres, windows coated with them would stay cleaner longer. The technology is a merger of two different chemical processes for growing polymer molecules:one grows tiny dots of polymer "seeds" on a flat surface, and the other grows vertical fibers out from the top of the seeds. The fibers grow until the scientists cut off the chemical reaction, forming a carpet of uniform height. The university will license the technology.