this is about photocatalytic application of conducting polymers,and basics of conduction and its applications in various field.

1. PHOTOCATALYTIC
APPLICATIONS .

2. CONDUCTING POLYMERS
Electronic conduction is described as the movement of free state electrons or
charges under potential gradient producing current or excitement of valance
band towards conduction band.
Polymer in general is a long chain organic macromolecule made up of linking
monomer that associated with carbon chain molecules. Most polymers are
considered as insulators because the aliphatic carbon chain that
constituents most part of polymers have filled electrons on their octet
configurations of covalent bonding. A new class of polymer that conduct
electricity was discovered by ALAN J HEEGER , ALAN G MACDIAMID, HIDEKI
SHERAKAWA leading to Nobel prize in 2000 in chemistry.

3. EXAMPLES OF CONDUCTING
POLYMERS
The most common conducting polymers are polythiophene (PTH) ,polypyrole (PPy),
polyaniline(PANI)
This cyclic feature is advantageous than those of aliphatic structures due to the
delocalisation of electrons in the pi bonded network within the conjugated bonds that
allows for doping process . Choice of dopant regard from neutral, ionic, organic or
polymer themselves.

4. BASICS ABOUT CONDUCTION
The large energy gap between the valance band and
conduction band in an insulator says that at an ordinary
temperature no electrons can reach the conduction
band.
In semiconductors the band gap is small enough that
thermal energy can bridge the gap for a small fraction of
the electrons.
In conductors there is no band gap since the valance
band overlaps the conduction band.
HOMO increases in the energy with increases
conjugation.
LUMO decreases in energy with increases conjugation.
The bandgap decreases with increases conjugation.

5. REASON FOR CONDUCTION
In a conjugated polymers, 3 of the valence bond electrons form strong sigma
bonds through sp2 hybridisation where electron are strongly localised.
The remaining unpaired electron of each carbon atom remains in a Pz orbital
it overlaps with a neighbouring Pz orbital to form a pi bond.
The pi electrons of these conjugated Pz orbital overlap to form an extended
Pz orbital system through which electron can move free.
However the conductivity of non doped polymers is low.

6. CLASSIFICATION OF
CONDUCTING POLYMERS
■ Intrinsically conducting polymers
(a)Conducting due to the conjugated system of pi electrons.
(b)Doped conducting polymers
■ Extrinsically conducting polymers
(a)Conductivity element
(b) Blended conducting polymers
■ Coordination or inorganic conducting polymers.

7. APPLICATION – KEY AREAS
Supercapacitors
Corrosion inhibition application
Photocatalytic application
Biomedical and antimicrobial application
Electrochemical gas sensors
Conducting polymer hydrogels for bio electronics
They are used in manufacturing of chemical sensors, electromagnetic shielding,
antistatic coating, corrosion inhibitors etc.
They are also used in compact electronic devices such as polymer based
transistors, LED, lasers.
They are used in microwave absorbent coating particularly radars absorptive
coating on stealth air craft
They are used in manufacturing of printed circuit board because it protect the
copper from corrosion and prevents the solderability.

8. CONDUCTING POLYMER
PROPERTIES
▶High melting and softening point
▶Excellent chemical ,thermal, oxidative stability due to low H2 content and
aromatic structure
▶Can form highly ordered crystalline thin film
▶Insoluble in many common solvent

9. CONDUCTING POLYMERS AS A
PHOTOCATALYST TO DEGRADE
WATER POLLUTANTS
Photocatalyst is a material that can sped the photocatalytic degradation
reaction with the aid of uv radiation such s sunlight, UV and visible light.
Photocatalytic degradation technology is one of the advanced oxidation
process (AOP) that involve semiconductor photocatalyst and oxygen to
produce radicals that degrade the pollutant. Photocatalyst degradation is
widely used for water treatment and environmental remediation, especially
emerging pollutants originating from agriculture and industrial activities. The
photocatalytic activity is very much influenced by crystal structure, particle
size, bandgap, dispersibility and hydroxyl of the catalyst .

10. PHOTOCATALYST ACTIVATION
MECHANISM STEPS
1. During this reaction the supplied photons will 1st exite the electrons located in the
valance band on the surface of a photocatalyst.
2. If the photons contain higher energy than the energy of bandgap the electron will
rise up into the conduction band thus leaving behind a hole (h+) in the valance
band. Thes separated holes and electrons can be recombined and release the
absorbed energy as heat.
3. The exited electrons in the conduction band will react with O2 molecules present
to form superoxide radicals (O2-) or hydroperoxide radicals (H2O)
4. These reactive oxygen species will induce pollutants degradation and produce
water and CO2 as biproducts.
5. The O2- can be further used again in secondary degradation steps were these
reactions could result in the oxidation of water molecules as the holes in the
valance band that produce hydroxyl radicals and hydrogen ions.
6. Lastly the OH would react with pollutants and results in H2O and CO2.

11. • A metal oxide semiconductor is the most suitable photocatalyst for the degradation
of pollutants ascribed to its suitable band gap position, non toxicity, low cost,
chemical and photonic stability, biocompatibility.
• DEMERITS- efficiency low, therefore conducting polymers is combined with a
semiconductor material to act as an important inhibitor of electrons hole pair
recombination
• Conjugated polymer therefore are a good light harvesters and promote carrier.
Among photocatalyst TiO2 is preferred because of its novel bandgap , easy
synthesis ,cheapness ,high photo activity, resistance to photo corrosion and high
oxidising power.
• Separation in photocatalytic composite that eventually increase the degradation
efficiency
• MERITS- easy to synthesize ,stable in environment.

12. CONDUCTING POLYMER BASED
PHOTOCATALYST
□ Conducting polymer have narrow bandgap thus they can absorb UV and visible light.
□ Conducting polymers were promising photocatalyst for dye decomposition.
□ An ideal conducting polymer photocatalyst should have a narrow band gap for absorbing
solar light, a perfect conjugated structure for fast transfer of charge carriers and a large
specific surface area for the absorbing target pollutant.
□ Nanofibers of PDPB monomer using a hexagonal phase soft template was prepared.
□ They exhibit strong catalytic activity for the degradation of model pollutants.
□ In this case photogenerated O2- radicals played a role in the oxidation of pollutants.
□ The PDPB nanostructure reduced the recombination of photogenerated and less
defective chain structure
□ Their photocatalytic performance of traditional conducting polymers such as Ppy,PANI,
PTH are poor.
□ Their performance can be greatly improved by incorporating metal compounds to restrict
the recombination of charge carriers.
□ Actually in this case conducting polymers acted as a photosensitizers to absorb visible
light.

13. PHOTOCATALYTIC
APPLICATIONS
Generally TiO2 exhibit 3 phases – anatase, rutile, brookite
Anatase have good photochemical behaviour due to its high band gap
The process behind dye degradation includes incidence of light on
photocatalyst photo induced holes, the accumulation of electron on the
semiconductor surface initiation of redox reaction and degradation of the
reaction process
The photocatalyst still give good activity after 3 cycles of irradiation
It has reusable property

14. CATALYST FOR WATER
SPLITTING
Splitting of water into H2 and O2 gases can convert solar power to clean
chemical energy. The efficiency and rate of photocatalyzed water splitting are
controlled by efficiency of charge separation and the electrochemical
properties of photocatalyst. Generally pure conducting polymers are not able
to photocatalyzed water splitting because of fast recombination of
photogenerated charge carriers. They can be used as sensitizers for other
photocatalyst to improve their performance under visible light.

15. SUPERCAPACITORS
In effort of developing eco friendly ,high energy ,renewable energy
resources ,including supercapacitors fuel cells and wind energy .
Nowadays ,supercapacitors are of great commercial interest because of the
future markets fir wearable devices, electric vehicles etc. the main difference
conventional capacitors and supercapacitors devices store 100 times more
energy than a dielectric capacitor. Also high speed charge ,discharge cycle ,
high energy, power density also good life cycle.
supercapacitors
Psuedo capacitors
Electrostatic double layer
capacitors
Hybrid capacitors

16. MERITS
Easy fabrication
Electrical conductivity
High specific capacitance
High cyclic stability
Easy synthesis

17. CORROSION INHIBITION
APPLICATIONS
Conducting polymers and conducting polymer pigment paint coatings play a
very potent role in corrosion inhibition.
A possible components of corrosion resistant coating system due to their
ability to maintain stable passivity of a metal by an anodization process
coupled with O2 reduction on the surface of the film.
They form a metal oxide interface layer between metal and coating.
Also in the case of phosphate pigments , specifically phenyl phosphonic acid
they can form a metal phosphate in the film on the metal surface and their
phosphate layer inhibits corrosion effectively.

18. POLYPHENYLENE
High light harvesting property along with energy transfer through its
conjugated backbone. The reduced size effect of Pd causes a better catalytic
reaction. From the UV-VISIBLE absorption data it is clear that the catalyst has
better light absorption and the composite has higher conversion efficiency in
the transition of p-Nph to p-Aph . The Pd/polyphenylene catalyst show better
reusability after a series of reaction cycles. The light energy harvesting of
polyphenylene causes the migration of electron towards Pd surface.
Resulting in high electron density over the Pd surface. It also causes better
H2 activation and thereby better photocatalytic activity .

19. POLYANILINE
Electron densities and bond energy on the surface of polyaniline while making
a composite with CdO enhances the dye degradation up to 7 times more than
pristine polyaniline. It has dye degradation ability. CdO concentration should
be optimum .better activity with Congo-red dye.it is used against methylene
blue and malachite green.
TiO2 has wide energy gap .due to the excitation in sunlight is limited and
excitation shows best under UV. When making a composite with conjugative
polymers the band gap is reduced compared to pristine and TiO2. this is why
TiO2 composite absorbs more photons and degradation of dyes is enhanced.
Photogenerated holes and electron rection the presence of O2 and water to
form photo induced anions like O2- and OH- .these two photo anions are
responsible for dye degradation.

20. POLYANILINE – GRAPHENE
COMPOSITE
When visible light is irradiated on the composite the photogenerated electron
in the conduction band of polyaniline migrate towards the fermi level of
graphene. This is because both conduction band of polyaniline and the fermi
level of graphene is same. Migrated electron in the surface of graphene react
with dissolved O2 to form super oxide radical ion. This react with water to
form H2O2. H2O2 react with photogenerated electron and photogenerated
holes in the Cl3 of polyaniline . The generated OH is responsible for dye
degradation.

21. CO2 REDUCTION
■ Process using light irradiation
■ Convert CO2 to hydrocarbon
■ CO2 cannot absorb sunlight spectrum because CO2 is very stable
■ So photoreduction needs support from photosensitizers.
■ Photosensitizers are semiconductor that can generate electron hole pairs
■ PANI,PPy,PEDOT are combined with metal oxide for CO2 reduction.

22. OXIDATION OF HEAVY METALS
▶Heavy metals are harmful to environment it is difficult to remove.
▶A mesoporous titanium polyaniline nanocomposite can remove chromium
ions.
▶ Not only on the surface but also in bulk.

23. POLYMER MAGNETS
Plastic – non metallic magnets from organic polymer eg. PANI combined
with tetracyanoquinodimethane (TCNQ) as an acceptor-mimic metallic
magnets. Magnetism from fully pi conjugated nitrogen containing backbone
with molecular charge transfer side groups. These cause the molecule to
have a high density of localised spin-coupling of their magnetic fields. Plastic
magnets can be used in computer hardware-disc drives, information storage,
light weight motors, in medical as a pace maker and cochlear implants.
Plastic magnet affected by light – blue light will increase magnetic field and
green will decrease it depending on structure.

24. CONDUCTING POLYMER BASED
BIO SENSORS
Devices either used to monitor living systems or incorporating biotic elements.
Relays on molecular recognition and its transductor into a measurable output.
Conducting polymer with ionic functionalities interface the electronic and
photonic process of bio molecules (polymer electrolyte) like protein,DNA,RNA
etc.Interactions due to electromagnetic forces electrostatic,dipolar,hydrogen
bonding and vander Waals – conformational change/aggregation modifies
the photo absorption and emission of conducting polymers used for
transduction.

25. • -conjugated polymer bio sensing
• -DNA hybridisation
• -detection of protein conformational changes
• -tissue and cell staining
• -nerve cell communication
• -bio compatibility of conjugated polymer
• -self assembly of bio organic electronic nanodevices
• -DNA mediated self assembly
• -protein fibril mediated self assembly
• -soft lithography techniques for pattern generation in bio detection.

26. Conducting polymers
metal
Plastic
batteries
photoconduct
ors
LED
photocopies
Conducting
Composites
Super
capacitors
connecting
piezoelectric
traducer
s
Solid state
photochemical
reaction
Optical
storage
Solid state
sensors
Conducting
surface EMI/ESD
OPTOELECTRONICS
LED,white light
source, solar cell
ferromagnetism
Magnetic
recording
electrochromi
c
Display
device
Non linear optical
phenomena
Frequency
doubler
superconductors
Josephson junction
computer logic
High field
Magnetic
generators

27. CHALLENGES AND
PROSPECTUS
□Conducting polymer based catalysts include inherent conducting polymers.
□ Conducting polymer composites and conducting polymer derived hetero atom
doped carbons.
□Catalytic mechanism have not yet been extensively revealed and the practical
applications of conducting polymer based catalyst still face several challenges.
□The exact catalytic sites of these catalyst and the catalytic mechanism, are still
unclear, needing systematically studies .
□ The performance of these catalyst strongly depend upon their conductivities
specific surface areas electrochemical activities and stabilities.
□Thus effective techniques for preparing conducting polymer nanostructures with
excellent electrical and electrochemical properties are required.
□ Precise control in their compositions microstructures and interactions between
different component are big challenges

28. THANK YOU
Lakshmi manoj