01-03-2009, 01:59 PM
Polymers are organic materials consisting of long chains of single molecules. Polymers are highly adaptable materials, suitable for myriad applications. Until the 1970s and the work of Nobel laureates Alan J. Heeger, Alan G. MacDiarmid and Hideki Shirakawa, polymers were only considered to be insulators. Heeger et al showed that polymers could be conductive. Electrons were removed, or introduced, into a polymer consisting of alternately single and double bonds between the carbon atoms. As these holes or extra electrons are able to move along the molecule, the structure becomes electrically conductive.
Thin Film Electronics has developed a specific group of polymers that are bistable and thus can be used as the active material in a non-volatile memory. In other words, the Thin Film polymers can be switched from one state to the other and maintain that state even when the electrical field is turned off. This polymer is "smart", to the extent that functionality is built into the material itself, like switchability, addressability and charge store.
This is different from silicon and other electronic materials, where such functions typically are only achieved by complex circuitry. "Smart" materials can be produced from scratch, molecule by molecule, allowing them to be built according to design. This opens up tremendous opportunities in the electronics world, where "tailor-made" memory materials represent unknown territory
Polymers are essentially electronic materials that can be processed as liquids. With Thin Film's memory technology, polymer solutions can be deposited on flexible substrates with industry standard processes like spin coating in ultra thin layers. Digital memory is an essential component of many electronic devices, and memory that takes up little space and electricity is in high demand as electronic devices continue to shrink Researchers from the Indian Association for the Cultivation of Science and the Italian National used positive and negative electric charges, or space charges, contained within plastic to store binary numbers Research Council. A polymer retains space charges near a metal interface when there is a bias, or electrical current, running across the surface.
These charges come either from electrons, which are negatively charged, or the positively-charged holes vacated by electrons. We can store space charges in a polymer layer, and conveniently check the presence of the space charges to know the state of the polymer layer. Space charges are essentially differences in electrical charge in a given region. They can be read using an electrical pulse because they change the way the devices conduct electricity.