Polyaniline - A Conductive Polymer Topics Covered Background
A Material of Substantial Promise
Emerging Applications
Challenges Ahead
Developments
Applications
Background Amongconducting plastics polyaniline stands out due to its outstandingproperties. It is one of the so-called doped polymers, in whichconductivity results from a process of partial oxidation or reduction.Polyaniline compounds can be designed to achieve the requiredconductivity for a given application. The resultant blends can be asconductive as silicon and germanium or as insulating as glass. Anotheradvantage is that it is both melt and solution processable. This meansthat the compound can be easily mixed with con
ventional polymers and that it is easy
to fabricate polyaniline products into required
shapes.
Moreover, products consisting of polyaniline compounds can be easily disposed of without environmental risks.
A Material of Substantial Promise Emerging Applications In2000, demonstrating what can be achieved by using polyanilinecompounds, Philips designed and fabricated an all-polymer integratedcircuit. The circuit has 326 transistors and more than 300 handedcontacts. The transistors of the circuit were manufactured by using UVlithography, taking advantage of the fact that strong UV radiationreduces the conductivity of polyaniline by a factor of ten.
Inelectronics the main advantage of the use of polymers is the ease atwhich they can be processed into required shapes. The resultingcircuits are lightweight and flexible, but not yet as fast as siliconcomponents.
The conductivity of polyanilinemakes it an ideal shield against discharges of static electricity. Thatis why polyaniline compounds have been used in the packaging ofelectronics products.
Polyaniline compoundsare being tested for use against electromagnetic radiationManufacturers hope that one day printed circuit boards, electrochromicwindows in houses and cars and conductive fabrics will containpolyaniline compounds.
Challenges Ahead Thereis still some need to improve the stability of conducting polymerswhile at the same time their synthesis should be simplified and costreduced. Electrical conductivity of these materials could be improvedfurther by reducing defects in the long polymer chains that carry thecurrent.
In the years ahead, it may becomepossible to produce cheap plastic electronic circuits that can be used,for instance, in diagnostic test kits that per form complex testsrapidly and can be disposed of after use.
Similarlyin mobile communications there is a great need for improving theproperties of displays in handheld devices. Opportunities abound, butmuch research and development is still needed before new classes ofsuitable materials will emerge.
Developments Thepotential of conducting polymers was recognised in 2000 by the NobelCommittee, which awarded the 2000 Prize in chemistry to the threeinventors of conducting polymers. Their article on the topic waspublished in 1977. Their subsequent research has led to the formationof joint venture companies, several patents, polymer diodes andelectroluminescent devices as well as producing the world’s firstorganic light-emitting diode displays.
Applications ·
Fibres
·
Antistatic and other coating
·
Films
·
Diodes
·
Electroluminescent Devices
·
Displays
·
Printed circuit boards
·
Electrochromic windows in houses and cars
·
Conductive fabrics
Authors: Mr. Juhani Pesälä, Ms. Soili Peltonen and Mr. Jukka Perento
Source: Industrial Horizons Magazine, April 2001.
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发表于 2008-10-10 04:48:03
