2. Conductive polymers are organic polymers that conduct electricity.
These polymers are not thermoplastics but like insulating polymers,
they are organic materials.
They can offer high electrical conductivity but do not show similar
mechanical properties to other commercially available polymers.
Conductive polymers are prepared by oxidative coupling of
In 1977, Shirakawa, MacDiarmid, and Heeger were able to increase
the conductivity of trans polyacetylene samples, after doping, to a
conductivity of about 1000 S/m or 1 S/cm. They got Nobel Prize in
Polyacetylene has been produced by several methods, many utilizing the
Zeigler–Natta polymerization systems.
Both cis and trans isomers exist. The cis polyacetylene is copper-
colored with films having a conductivity of about 10-8 S/m. By
comparison, the trans-polyacetylene is silver-colored with films
having a much greater conductivity on the order of 10-3 S/m.
The cis isomer is converted into the thermodynamically
more stable trans isomer by heating (150 °C).
Conductivity is greatly increased when the trans-
polyacetylene is doped (to about 10^2 – 10^4 S/cm).
5. CONJUGATED CONDUCTING POLYMERS
The carriers of electron conducting polymers are free electrons and their
common characteristic is a long π-conjugated system in the molecular
skeleton, which results in delocalised electrons.
These molecules are called conjugated conducting polymers.
To efficiently increase the movement of electrons in the π-system, the energy
level difference caused by energy band splitting should be reduced to easily
overcome the energy difference between the full and empty bands.
They are widely used in organic solar cells (OSCs), organic field effect
transistors (OFETs), sensors, and colour-changing coatings.
10. Extrinsic conducting polymers
Those conducting polymers which owe their conductivity due
to the presence of externally added ingredients in them are
called extrinsically conducting polymers.
Extrinsically conducting polymers (ECP’s) are of two types.
These are: (1) conducting elements filled polymers(CEFP),
and (2) blended conducting polymers(BCP)
11. 1.CONDUCTING ELEMENTS FILLED POLYMERS
In this type, a conducting element is added to the polymer.
The conducting material will have more surface area and more porosity.
Therefore, the polymer acts as a binder to hold the conducting elements
together in solid entity.
Thus, conductivity of these polymers is due to the addition of external
Upon addition of conducting element, the polymer will have a property of
that conducting element and it will start conducting electricity.
Poly(3-hexylthiophene) (P3HT) is a derivative of
polythiophene. The two major steps for the preparation is
Grignard metathesis polymerization, and quenching reaction.
P3HT is popular because of its wide availability, low cost,
well-known morphology, and easy processability.
P3HT is a semicrystalline polymer and its backbone is made
up of isolated rings and linear side chains. This structural
arrangement enables the freedom to sample conformational
It is used in personal mobile phone charger, solar panel,
15. 2.Blended conducting polymers
These types of polymers are obtained by blending a conventional
polymer with a conducting polymer either physically or chemically.
This blend of polymers conduct electricity.
Such polymers can be easily processed and possess better physical ,
chemical and mechanical properties.
Examples: poly(styrene) (PS)–poly(phenylene oxide) (PPO) and
poly(styrene-acrylonitrile) (SAN)–poly (methyl methacrylate)