SHARDA UNIVERSITY

APPLIED CHEMISTRY CHY-102

CONDUCTING POLYMERS

SUBMITTED BY:-o KUNAL KAPUR

o MD.MANJAR HUSSAIN

o ANIMESH JAISWAL

o KAVISH SATIJA

o JITESH CHAWLA

o AKSHEY BAJAJ

SUBMITTED TO:- DR.NOOPUR SHRIVASTAV

CONDUCTING POLYMERS

A polymer which can conduct electricity is termed as conducting polymer.

EXAMPLES:

1.Polyaniline is used to make rechargeable batteries in the shape as flat buttons or as laminated rolled films.

2.Polypyrrole is used in ‘smart’ windows .These smart windows can change their colour in response to changes in temperature or amount of sunlight. The colour change is from a transparent yellow-green to blue-black.

ADVANTAGES It is being said that ‘one day conducting

polymers may be used in place of metals in electrical wiring.’.

Lighter weight.

They do not corrode.

CONDUCTING POLYMER

INTRINSICALLY CONDUCTING

POLYMERS

EXTRINSICALLY CONDUCTING

POLYMERS

INTRINSICALLY CONDUCTING

POLYMERS

CONDUCTING POLYMERS HAVING

CONJUGATION

DOPED CONDUCTING

POLYMERS

EXTRINSICALLY CONDUCTING

POLYMERS

CONDUCTING ELEMENTS FILLED

POLYMER

BLENDED CONDUCTING POLYMEERS

INTRINSICALLY CONDUCTING POLYMERS

These polymers have extensive conjugation in the backbone which is responsible for conductance.

CONDUCTING POLYMERS HAVING CONJUGATION

Such polymers contain conjugated pie-electrons in the backbone which increases their conductivity to a large extent.

Overlapping of conjugated pie-electrons over the entire backbone results in the formation of valence bands as well as conduction bands.

The valence band and the conduction bands are separated by a significant band gap.

Electrical conduction could occur only after thermal or photolytic activation of electrons to give them sufficient energy to jump the gap and reach into the lower levels of the conduction band.

EXAMPLES:

(1)POLYACETYLENE

(2)POLYPYRROLE

(3) POLYANILINE

DISADVANTAGEConductivity of these polymer, having conjugated pie-electrons in the backbone is not sufficient for their use in different applications.

DOPED CONDUCTING POLYMERS

These polymers have doping of positive or negative charge on polymer backbone.

Conductivities of previous type can be increased by creating positive or negative charge on polymer backbone by oxidation or reduction.

P-DOPINGIt is done by oxidation process.

Conducting polymers of previous type is treated with lewis acid (A) or with iodine vapour or iodine in CCl4.

N-DOPINGIt is done by reduction process.

Conducting polymer of previous type is treated with lewis base (B) like sodium naphthalide.

Conducting polymer

Polyaniline

Polypyrrole

Polythiophene

Dopants HCl BF4-,ClO4- Tosylate

Conductivity (S cm-1)

1000 500-7500 1000

FACTORS INFLUENCING THE CONDUCTIVITY OF ORGANIC POLYMERS

Conjugation length of the polymer chain.

Doping Level.

Temperature.

Frequency of current.

INTERSTING RANGE OF PROPERTIES OFFERED BY INTRINSICALLY CONDUCTING POLYMERS

Conductivity.

Ability to store a charge.

Ability to ion exchange.

Absorption of visible light to give coloured products.

Transparency to X-rays.

SUCCESSFUL APPLICATION DEPENDS ON ACHIEVING THE FOLLOWING FEATURES :

Advantage in processing.

Excellent properties in products.

Economy.

Good product stability.

More efficient recycling.

Demonstration of ecological advantages.

LIMITATIONS OF INTRINSICALLY CONDUCTING POLYMERS

Their conductivities are inferior to metal.

Improcessibility.

Poor mechanical strength.

Poor stability under exposure to common environmental conditions, particularly at elevated temperatures.

Poor storage stability leading to loss in conductivity.

MATERIAL CONDUCTIVITY

POLYACETYLENE 400000 S cm-1

Cu 600000 S cm-1

EXTRINSICALLY CONDUCTING POLYMERS

These polymers owe their conductivity due to the presence of externally added ingredients in them.

CONDUCTIVE ELEMENT FILLED POLYMER

In this, the polymer acts as the binder to hold the conducting element (such as carbon black, metallic fibers, metallic oxides,etc.) together in the solid entity.

Generally, special conducting grade C-Black is used as filler which has very high surface area, more porosity and more of filamentous properties.

ADVANTAGESo Good bulk conductivity.

o Low in cost.

o Light in weight.

o Mechanically durable and strong.

o Easily processable in different forms, shapes and sizes.

DISADVANTAGEo Addition of as little as 10% carbon black

will drastically reduce the tensile strength.

BLENDED CONDUCTING POLYMERS

These polymers are obtained by blending a conventional polymer with a conducting polymer. Such polymers possess better physical, chemical, electrical and mechanical properties and they can be easily processed.

For example :-

upto 40% of polypyrrole will have little efffect on tensile strength than obtained with a carbon-black filled compound at only 10% loading.

APPLICATIONS OF CONDUCTING POLYMERS

IN RECHARGEABLE BATTERIES

IN ANALYTICAL SENSORS

FOR MAKING ION-EXCHANGERS

IN ELECTROCHEMICAL DISPLAYS AND OPTICAL FILTERS

IN ELECTRONICS

IN PHOTOVOLTAIC DEVICES

THANK YOU FOR YOUR ATTENTION