Polypyrrole case study analysis part 2

1. Summary about the polymer
 Polypyrrole (PPy) is a type of organic polymer formed from by polymerization of
pyrrole.
 PPy is an insulator, but its oxidized derivatives are good electrical conductors. The
conductivity of the material depends on the conditions and reagents used in the
oxidation. Conductivities range from 2 to 100 S/cm
CH5190: Inroduction to Macromolecules
 Important states for discussion-
• Chemically pure doped,redoped and redoped conducting Ppy films doped with
different materials.
• Different nanostructures, (mainly nanoscopic tubules )composed of Ppy and
relation of conductivity with diameter.
Main applications in –
A. electronic devices ,
B. chemical sensors and also for
C. drug delivery etc.

2. Molecular arrangements
CH5190: Inroduction to Macromolecules
• Notes on conformation:
• With doping by camphor sulphonic acid crystallinity increases.
• ordering of the polymer chains is improved when the pores diameter decreases
and is responsible for the enhancement in conductivity.
• State variables which affect the molecular
arrangements. :
1. Doping with PP- on chemically pure Ppy films makes it thermally more stable.
2. (pTS-) ion doped film on SS-304 steel has good conductivity.
3. Nanoindentation shows that mechanical properties of polyphosphate and p-toluene
sulphonate doped films are better than perchlorate doped films.

3. Experimental technique/data 1
Chemical synthesis of polypyrrole: structure–properties relationship:Duchet, Roger Legras,
,Demoustier-Champagne:Synthetic Metals
Volume 98, Issue 2, 4 December 1998, Pages 113–122
CH5190: Inroduction to Macromolecules
Example of
property being
measured
• Nanostructures composed of polypyrrole (PPy)
obtained by chemically synthesizing Ppy,
measured for conductivity variation with
diameter.
Experimental
technique that is
used for the
measurement
• Nanostructures composed of PPy are obtained by
synthesizing it within the pores of microporous and
nanoporous Particle Track-etched Membranes (PTM)
• A field-effect gun DSM with an accelerating voltage of
1 kV was used to characterize the nanostructures
• Raman Spectra were recorded on spectrophotometer
Structural
information obtained
from the
measurement
• When order of the PPy chains increases, the electron
delocalization takes place at longer distance and
consequently, the conductivity increases.
• Raman data show that the ordering of the polymer
chains is improved when the pores diameter
decreases and is responsible for the enhancement in
conductivity.

4. Varrying Conductivity with Ppy
Tubule diameter
CH5190: Inroduction to Macromolecules

5. Experimental technique/data 2
For PPy films doped with different ions(p-toluene sulphonate
, perchlorate , polyphosphate)-
•Thermal stability
•Standard of conductivity
•Current-voltage curves
•Mechanical properties like hardness and elastic moduli
• Ppy films doped with counterions are electrodeposited on
stainless steel(SS-304) and ITO glass electrodes by
potentiostatic method.
• Composite films are studied with Fourier transform
spectra, integrated thermal analysis & SEM
• 4-probe measurement & in-situ nanotribolab for electrical
and mechanical properties.
• Polyphosphate ion doped Ppy film has best thermal
stability
• pTS- ion doped Ppy film has good conductivity.
• Mechanical properties are not so good in Ppy-perchlorate
films.
CH5190: Inroduction to Macromolecules
Example of
property being
measured
Experimental
technique that is
used for the
measurement
Structural
information
obtained from the
measurement
On the preparation and multiproperties of the polypyrrole films doped with different ions
By: Cheng Guanggui; Ding Jianning; Zhang Zhongqiang; et al.
SURFACE AND INTERFACE ANALYSIS Volume: 44 Issue: 7 Pages: 844-850 Published: JUL 2012

6. Thermal / thermodynamic
CH5190: Inroduction to Macromolecules
properties
 High Thermal and Environmental Stability
Thermal analysis establishes the higher stability of the CSA redoped
PPy film compared to other doped samples.
Polymer Crystalinity
Influences many of the polymer characteristics-mechanical strength,
opacity and thermal properties.
Semi-crystallinity is a desirable property - it combines the strength of
crystalline polymers with the flexibility of amorphous ones.
 High Electrical Conductivity
Use in specific technological applications -super capacitors, conductive
textiles and fabrics, mechanical actuators, electromagnetic
interference shielding devices, anti-static coatings.

7. Experimental technique/data 1
Thermal stability of electrochemically prepared polythiophene and polypyrrole:F
Mohammad,Calvert,Billingham;1995
CH5190: Inroduction to Macromolecules
Example of
property being
measured
• Weight loss
• Comparative stability with respect to
polyacetylene.
Experimental
technique that is
used for the
measurement
• Preparation of polypyrrole and application of current.
• Washing and drying a pumping line.
• Thermal gravimetric analysis technique
Structural
information
obtained from the
measurement
• Polypyrrole is more stable than polyacetylene
• undergo degradation reactions which involve two
steps, viz. loss of dopant and then degradation of
polymer backbone.
• Thermogravimetric analysis shows that polypyrrole
loses weight in more than one distinct stages in air
and nitrogen atmosphere.

8. TGA Analysis of Polypyrrole
CH5190: Inroduction to Macromolecules

9. Experimental technique/data 2
Novel polypyrrole films with excellent crystallinity and goodhermal stability:Pullarkat P. Jeeju,Sreekanth J. Varma,Puthampadath A. Francis XavierAugustine M.
SajimoSankaran JayalekshmiMaterials Chemistry and Physics
Volume 134, Issues 2–3, 15 June 2012, Pages 803–808
CH5190: Inroduction to Macromolecules
Example of
property being
measured
• Enhanced crystallinity
• Electrical Conductivity
• Good thermal stability
Experimental
technique that is
used for the
measurement
• HCl doped Py was prepared by chemical oxidative
polymerization of pyrrole using ammonium peroxi
disulphate as oxidant.
• Doped PPy was dedoped using ammonia solution and
then redoped with camphor sulphonic acid.
Structural
information obtained
from the
measurement
• The solution casted films exhibit semi-crystallinity and
good thermal stability.
• Percentage crystalinity estimated using XRD and
DSC analysis is about 65%.
• Raman studies support the enhancement in
crystalinity based on XRD and DSC data.
• The conductivity of the film is 30 times higher than
that of HCl doped sample.

10. Polypyrrole Crystalinity
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11. Polypyrrole crystalinity
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Sample Percentage of
Crystallinity
HCl doped PPy
(bulk)
40
Dedoped PPy
(bulk)
20
CSA redoped PPy
film
64

12. CH5190: Inroduction to Macromolecules
Summary
1. The sharp peaks in the Raman spectrum of the PPy film
support the increase in crystalinity of the film samples.[1]
2. The conductivity of the polypyrrole film increases with
decrease in polypyrrole tubule diameter.[2]
3. Doped films exhibit semi-crystalinity and better crystalline
structure.[4]
4. Polyphosphate ion doped Ppy film has best thermal
stability[3] and weight loss in Polypyrrole occurs in 3
distinct steps in isothermal condition.
1.Novel polypyrrole films with excellent crystallinity and goodhermal stability:Pullarkat P. Jeeju,Sreekanth J. Varma,Puthampadath A. Francis XavierAugustine M.
SajimoSankaran JayalekshmiMaterials Chemistry and Physics
Volume 134, Issues 2–3, 15 June 2012, Pages 803–8081
2. On the preparation and multiproperties of the polypyrrole films doped with different ions
By: Cheng Guanggui; Ding Jianning; Zhang Zhongqiang; et al.SURFACE AND INTERFACE ANALYSIS Volume: 44 Issue: 7 Pages: 844-850 Published: JUL 2012
3. Chemical synthesis of polypyrrole: structure–properties relationship:Duchet, Roger Legras, ,Demoustier-Champagne:Synthetic Metals
Volume 98, Issue 2, 4 December 1998, Pages 113–122
4. Thermal stability of electrochemically prepared polythiophene and polypyrrole:F Mohammad,Calvert,Billingham;1995

13. Interesting / confusing aspects
In TGA analysis ,methods to calculate comparative
stability with respect to polyacetylene.
In Raman spectra,methods to develop more
percentage of crystalinity.
Procedures to reduce Ppy tubule diameter for
increase in conductivity.
CH5190: Inroduction to Macromolecules
Reference, author, journal, year