Remembering, on the cheap
Peter Weiss
Radio-equipped electronic identity tags and sensors may soon broadcast prices, expiration dates, and other useful information from myriad objects, ranging from aspirin bottles to zoo cages. Now, researchers in the Netherlands have demonstrated a new type of electronic memory that they say could make those tags both physically tough and extraordinarily cheap.
TWIST 'N' STORE. A strand of ferroelectric plastic memory, modeled here, is caught in act of switching between a 1 and 0 state. Hydrogen atoms (grey) and fluoride atoms (green) swap up-down orientations in a wave that sweeps along the carbon-based strand (black).
Naber
The key is to make the memory out of two types of plastic, says Ronald C. G. Naber of the University of Groningen. One is a semiconducting polymer. The other, chemically similar to Teflon, is ferroelectric: It becomes electrically polarized when exposed to an electric field (SN: 8/9/03, p. 86: Available to subscribers at http://www.sciencenews.org/articles/20030809/fob7.asp).
Making transistors by patterning layers of these ingredients yields flexible devices that can retain bits of digital information, even when there's no electrical power. Naber and his colleagues at Groningen and at Philips Research Laboratories in Eindhoven describe their new memory gadgets in the March Nature Materials.
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References:
Naber, R.C.G., et al. 2005. High-performance solution-processed polymer ferroelectric field-effect transistors. Nature Materials 4(March):243–248. Abstract available at http://dx.doi.org/10.1038/nmat1329.
Further Readings:
Goho, A. 2004. Flexible e-paper: Plastic circuits drive paperlike displays. Science News 165(Jan. 31):67. Available at http://www.sciencenews.org/articles/20040131/fob1.asp.
Weiss, P. 2004. Inside plastic transistors: Crystal-clear window opens on hidden flows. Science News 166(July 24):51. Available to subscribers at http://www.sciencenews.org/articles/20040724/fob2.asp.
______. 2004. Electronic skin senses touch. Science News 165(Jan. 17):45. Available to subscribers at http://www.sciencenews.org/articles/20040117/note10.asp.
______. 2003. Electric foam: Scientists uncover basis of material oddball. Science News 164(Aug. 9):86. Available to subscribers at http://www.sciencenews.org/articles/20030809/fob7.asp.
Sources:
Ronald C.G. Naber
Materials Science Centre
University of Groningen
Nijenborgh 4
9747 AG Groningen
The Netherlands
From Science News, Volume 167, No. 12, March 19, 2005, p. 189.
