1 Treatment with halogen was called.
"doping- by analogy with the doping of semiconductors. The "doped- form of polyacetylene had a.
conductivity of 105 Siemens per meter, which was higher than that of any previously known polymer. As a.
comparison, teflon has a conductivity of 10-16.
S m-1and silver and copper 108 S m-1.
A key property of a conductive polymer is the presence of conjugated double bonds along the backbone of the.
polymer. In conjugation, the bonds between the carbon atoms are alternately single and double. Every bond.
2.
contains a localised "sigma- (?) bond which forms a strong chemical bond. In addition, every double bond.
also contains a less strongly localised "pi- (?) bond which is weaker. However, conjugation is not enough to.
make the polymer material conductive. In addition - and this is what the dopant does - charge carriers in the.
form of extra electrons or -holes- have to be injected into the material. A hole is a position where an electron.
is missing. When such a hole is filled by an electron jumping in from a neighbouring position, a new hole is.
created and so on, allowing charge to migrate a long distance.
Today conductive plastics are being developed for many uses, such as in corrosion inhibitors, compact.
capacitors, antistatic coating, electromagnetic shielding of computers, and in "smart- windows that can vary.
the amount of light they allow to pass, etc. A second generation of electric polymers has also appeared (see.
below) in, e.g., transistors, light-emitting diodes, lasers with further applications such as in flat television.
screens, solar cells, etc. Polymers have the potential advantages of low cost and that they can be processed,.
e.g., as film. We may soon be seeing electroluminescent plastics papered on walls for illumination.
What is electrical conductivity?.
Conductivity is defined by Ohm's law:.
U = R I, (1).
where I is the current (in Amperes) through a resistor and U is the drop in potential (in Volts) across it.
