viva phd _emma ziezie

STUDIES OF STRUCTURAL, THERMAL, OPTICAL AND ELECTRICAL BEHAVIOUR OF CONDUCTING POLYMER

POLPYRROLE, POLYPYRROLE/ZEOLITE AND POLYPYRROLE/BISMUTH OXIDE CONJUGATED SYSTEMS

1 Department of Physics, Faculty of Science, Universiti Putra Malaysia, MALAYSIA2 Department of Chemistry, Faculty of Science, Universiti Putra Malaysia, MALAYSIA

EMMA ZIEZIE MOHD TARMIZI Viva PhD presentation

PROF. DR. ZAINAL ABIDIN TALIB1, ASSOC. PROF. DR HALIMAH MOHAMED KAMARI1,PROF. ANUAR KASSIM2

Introduction of polymer, conducting polymer, Polypyrrole, Zeolite and Bismuth oxide

Applications

Objectives of the Study

Approaches & Research Methodology

Results and Discussion

PART 1 & 2 : Preparation of Samples

PART 3 & 4: Measurements: XRD, ED-XRF, FTIR, FESEM, DRS, Laser Flash, TGA, ESR & VDP

Conclusions

Research Contributions

PRESENTATION OVERVIEW

INTRODUCTION

Polymers are formed of a very large molecules (macromolecules) created by

polymerization of smaller subunits.

llustration of a Polypeptide macromolecule (Source: Wikipedia)

Polymers (or plastic) are known to have good insulating properties

Polymers are one of the most used materials in modern world. Their uses and

applications range from containers to clothing.

A. J. Heeger, Alan G. MacDiarmid, and Hideki Shirakawa

“for the discovery and development of electrically conductive polymers- polyacetylene”

Conductive Polymers

How can plastic become conductive? Plastics are polymers, molecules that form long chain repeating themselves like a

necklace.

In becoming electrically conductive, a polymer has to imitate a metal

its electron need to be free to move and not bound to the atoms.

Two conditions to become conductive:-

1.) the polymer must consists of alternating single & double bonds

In conjugation system, the bonds between the carbon atoms are alternately single and

double. Every bond contains a localised “sigma” (σ) bond which forms a strong chemical

bond. In addition, every double bond also contains a less strongly localised “pi” (π) bond

which is weaker.

Simplest chemical structure of Polyacetyelene with (Source: Nobelprize.org)

However this is not enough,

2.) the plastic has to be disturbed either by removing electron from (oxidation) or

inserting them into (reduction) the material. The process is known as Doping.

There are two types of doping:-

a.) p-doped (oxidation) – removing electron from its backbone, leaving hole in the form

of positive charge that can move along the chain.

b.) n-doped (reduction) – adding electron from its backbone

Changing the oxidation level of conjugated polymer means changing the number of the

electron on its backbone.

The game in the illustration above offers a simple model of a doped polymer. The

pieces cannot move unless there is at least one empty "hole". In the polymer each

piece is an electron that jumps to a hole vacated by another one. This creates a

movement along the molecule - an electric current.

NH

NH

NH

HN

HNN

HN

HN

NH

NH

HNN

HNN

+

+

Electron Acceptor

Electron Acceptor

polaron

bipolaron

HN

HNN

HN

Polaron and bipolaron formation on backbone of Polypyrrole.

Doping – Better Molecule Performance

Conductivity of conductive polymers compared to those of other materials, from quartz

(insulator) to copper (conductor).

Pyrrole

Pyrrole:

heterocyclic aromatic organic compound

a five-membered ring (formula molecule: C4H4NH)

high conductivity

can be prepared by various method such as chemical, electrochemical, vapor

phase, etc

various metallic salts have been employed to polymerize pyyrole :-

FeCl3, Fe(NO3)3, Fe(SO4)3 etc conductivity between 10-5- 200 Scm-1

Zeolite & Bismuth OxideZeolite are crystalline aluminosilicate minerals

Occurs naturally (volcanic rocks & ash layer react

with alkaline groundwater), also produced industrially

Contains various kinds of channel and cages with

different sizes and geometry

Widely use as sorbents, ion exchangers and catalyst

Bismuth (III) oxide is perhaps the most industrially important

compound of Bismuth

It has five crystallographic polymorph

Low toxicity & widespread use in pharmaceutical

Environmental friendly

High electrical conductivity, chemical stability

Solar cell

Liquid

Electrolyte

Rechargeable Batteries

Electrochromic

Display

Electrochemical Storage

Fuel cell

APPLICATIONS

Sensors

OBJECTIVES OF THE STUDY

To prepare an intrinsically conducting compound Polypyrrole through chemical oxidative polymerization method.

optimum ratio of oxidation/monomer, synthesis duration and polymerization conditions

To produce Polypyrrole/Zeolite and Polypyrrole/Bismuth oxide with optimal physical properties stability, morphology, thermal, opticcal and electrical responses.

To study the effect and response response between Zeolite which is microparticleand Bismuth oxide, a macroparticle with the host polymer at different concentrations.

To study the effect of Polypyrrole, Polypyrrole/Zeolite and Polypyrrole/Bismuth oxide intrinsically conducting polymer of different concentration levels and percentage of primary and secondary doping agents through various techniques:-a.) Fourier Transform Infrared (FTIR) Spectroscopyb.) Thermal Gravimetry Analysis (TGA)c.) X-Ray Diffraction (XRD)d.) Field Emission Scanning Electron Microscopy (FESEM)e.) Energy Dispersion X-Ray Flourescence (ED-XRF)

To investigate the temperature, current and applied voltage dependence on the thermal, magnetic and electrical properties of all samples using :a.) Laser Flash Techniqueb.) Electron Spin Resonance (ESR)c.) Van Der Pauw (VDP) method

To find correlation and possible applications of both systems.

Experimental design conducted in this research

Analysis Report WritingComputational

Study – ORIGIN &

EXCEL software

Polypyrrole/Zeolite Polypyrrole/Bismuth oxidePolypyrrole

Optimum ratio oxidation/monomer, synthesis duration & polymerization condition

to obtain good conductive sample

Measurements

Diffuse Reflectance Spectroscopy (DRS)

FESEMED-XRF

TGA

XRD

Morphology Studies

Preparation of sample for measurement

[Powder and Palletizing according to measurement]

Preparation of sample – Chemical oxidative polymerization menthod

Double distillation fo Pyrrole

Part 1

Part 2

Part 3

Part 4

FTIR

Temperature,Current & Voltage

Dependence StudiesLaser Flash ESR VDP

APPROACHES & RESEARCH METHODOLOGY

RESULTS & DISCUSSION

The optimum concentration of Pyrrole is 0.2 M

Water bath is needed during the stirring process to maintain the temperature of the

solution as increment temperature could cause to the failure of obtaining the

conductive sample

The optimum time for completing the polymerization process is 6 hours

7 tonne is the most favorable pressure value to form a good pellet

0 5 10 15 20 25 30 35 40

876543

Inte

nsi

ty (

a.u

.)

Diffraction angle (2

Zeolite

1 MR

1 MR 5%Z

1 MR 15%Z

1 MR 10%Z

1 MR 20%Z

1 2

0 5 10 15 20 25 30 35 40

Inte

nsi

ty (

a.u

.)

Diffraction angle (2

Bi2O

3

1 MR

1 MR 5%B

1 MR 15%B

1 MR 10%B

1 MR 20%B

431

2 6

5


The effect of (a) Zeolite and (b) Bismuth oxide on 1 MR Polypyrrole

All pristine Polypyrrole (only with the presence of primary doping agent) showing amorphous nature with a broad halo observed at

around 2 value of 25o.

Some degree of crystallinity is observed after introduction of Zeolite and Bismuth oxide as secondary doping agents in Polypyrrole

Zelite and Bismuth oxide overlapped the broad halo which indicate higher crystallinity of Polypyrrole/Zeolite and

Polypyrrole/Bismuth oxide

a b


Element(%)

Sample

Cl Fe Si Na K Al Mn

Zeolite - 19.017 33.102 23.257 20.460 1.659 0.722

1MR 96.415 1.015 - - - - -

1MR 5%Z 65.486 8.186 11.626 4.945 7.244 1.380 0.219

1MR 10%Z 46.716 12.915 19.617 8.045 9.328 1.853 0.356

1MR 15%Z 36.067 16.942 23.442 9.459 9.500 1.648 0.452

1MR 20%Z 26.772 18.929 30.327 7.658 10.582 1.910 0.509

Chlorine and iron arises from primary doping agent and confirmed the presence in every systems

Contents of Zeolite is observed

made up of silicate, natrium, kalium and iron

Zeolite presence is confirmed in each Polypyrrole/Zeolite samples

As Zeolite is increased, it is observed that chlorine content decreased

could be due to formation complex between chlorine and Zeolite (negatively-charge balance of the surface could have

replace the role of chlorine)

Elemental analysis of Polypyrrole and Polypyrrole/Zeolite.

Element(%)

Sample

Cl Fe Bi

Bismuth

oxide- - 99.800

1MR 96.415 1.015 -

1MR 5%B 27.577 0.629 70.103

1MR 10%B 22.212 0.798 76.438

1MR 15%B 15.652 0.538 81.348

1MR 20%B 14.446 0.485 83.916


Elemental analysis of Polypyrrole and Polypyrrole/Bismuth oxide.

Chlorine is observed in every samples of Polypyrrole/Bismuth

oxide

The presence of Bismuth is confirmed in every samples of

Polypyrrole/Bismuth oxide

Shows same mechanism as in Polypyrrole/Zeolite system

contents of iron and chlorine begin to fall-off


The successful of poly,erization of Polypyrrole,

Polypyrrole/Zeolite and Polypyrrole/Bismuth oxide is

confirmed as all the crucial bands were observed.

1600 1400 1200 1000 800 600 400

1 MR 20%Z

1 MR 15%Z

1 MR 10%Z

1 MR 5%Z

1 MR

Zeolite

Tra

nsm

itta

nce

(A

rb u

nit)

Wavenumber, cm-1

1536

14591298

1159 1016 879 759

667563

429

The FTIR spectra of 1 MR Polypyrrole and

Polypyrrole/Zeolite conjugated system.

Assignment

Wavenumber (cm-1)

pristine 5 wt% 10 wt% 15 wt% 20 wt%

v (C=C) of Pyrrole

(aromatic type)

1526 1533 1533 1534 1536

v (C-N) of Pyrrole 1446 1442 1446 1449 1459

v (C-C) of Pyrrole 1285 1293 1294 1295 1298

v (C-C) of Pyrrole /

vibarations of Zeolite

lattice

1140 1151 1152 1153 1159

δ (C-H) and δ (N-H)

of Pyrrole

1021 1028 1025 1025 1026

Assignments of FTIR absorption bands of 1 MR Polypyrrole (PPy) and



1600 1400 1200 1000 800 600 400

1 MR 15%B

1 MR 20%B

1 MR 10%B

1 MR 5%B

1 MR

Bi2O3

Wavenumber, cm-1

Tra

nsm

itta

nce

(A

rb u

nit)

1520 1443 1283 11321016

841 759656

589500 402

The FTIR spectra of 1 MR Polypyrrole and

Polypyrrole/Bismuth oxide conjugated system.

Assignment

Wavenumber (cm-1)

pristine 5 wt% 10 wt% 15 wt% 20 wt%

v (C=C) of Pyrrole

(aromatic type)

1526 1533 1533 1534 1536

v (C-N) of Pyrrole 1446 1442 1446 1449 1459

v (C-C) of Pyrrole 1285 1293 1294 1295 1298

v (C-C) of Pyrrole /

vibarations of Zeolite

lattice

1140 1151 1152 1153 1159

δ (C-H) and δ (N-H)

of Pyrrole

1021 1028 1025 1025 1026

Assignments of FTIR absorption bands of 1MR Polypyrrole (PPy)

and Polypyrrole/Bismuth oxide conjugated system.

Polymer identification through bonds and functional

groups present in the polymer

Crucial and major bands for all samples Polypyrrole,

Polypyrrole/Zeolite and Polypyrrole/Bismuth oxide

associated below 1600 cm-1.


aa b c

FESEM image of (a) 1 MR Polypyrrole and 20% of impregnanted (b) Zeolite & (c) Bismuth oxide in 1 MR Polypyrrole

Polypyrrole give globular or nodule morphology antwined

forming cauliflower like structures continously giving rise

to three dimensional structure.

Didn’t have any particular direction and appeared to be

connected to each other at variant angles.

Exhibit a denser and more compact morphology as

primary doping agent increased,

Zeolite exhibit a dense and more compact morphology.

Globular structure can be seen distributed throughout the

Zeolite external surface.

In case of Polypyrrole/Bismuth oxide, small round

particles as well as some particle pattern with diffrerent

dimension scattered in the system.

Higher concentrations of secondary dopi ng agent caused

the particle become smaller, compact, higher porosity and

surface area.


200 300 400 500 600 700 800 900 1000 1100 1200

50

60

70

80

90

100

110

1 MR

1 MR 15 % Z

1 MR 10 % Z

1 MR 5 % Z

Zeolite

Weig

ht (%

)

Temperature (K)

1 MR 20 % Z

TGA thermogram of 1 MR Polypyrrole and


Pristine 1 MR Polypyrrole shows first significant

weight loss as early as 326 K with weight loss of

5.416%

3 stages of weight loss observed with total

weight loss of 51.250 %

Pure Zeolite only recorded one stage of weight loss at

427 K with a total weight loss of 12.590 %

1 MR Ppy with 20% Zeolite shown lowest weight loss

Samples Step 1

293-403 K

Weight loss

(%)

Step 2

404-663 K

Weight loss

(%)

Step 3

664-1173 K

Weight loss

(%)

Total

weight loss

(%)

Zeolite -Tmax=427 K

12.590-

12.590

1 MR PPy

Tmax=326 K

5.416

Tmax= oC

Tmax=459 K

7.342 38.492 51.250

1 MR PPy 5 %

Zeolite

Tmax=328 K

4.742

Tmax=471 K

9.104 22.691 36.537

1 MR PPy 10

% Zeolite

Tmax=330 K

7.398

Tmax=558 K

10.508 21.110 39.016

1 MR PPy 15

% Zeolite

Tmax=337 K

9.372 25.589 - 34.961

1 MR PPy 20

% Zeolite

Tmax=329 K

3.747 22.593 - 26.700

TGA data for Polypyrrole and Polypyrrole/Zeolite conjugated systems.

200 300 400 500 600 700 800 900 1000 1100 1200

20

30

40

50

60

70

80

90

100

110

Temperature (K)

Weig

ht (%

)

1 MR 20 % B

Bi2O

3

1 MR 15 % B1 MR

1 MR 5 % B

1 MR 10 % B


TGA thermogram of 1 MR Polypyrrole and

Polypyrrole/Bismuth oxide conjugated system.

Samples

Step 1

293-403 K

Weight loss

(%)

Step 2

404-663 K

Weight loss

(%)

Step 3

664-1173 K

Weight loss

(%)

Total

weight

loss

(%)

Bismuth oxide -

Tmax=538K

0.466

Tmax=757 K

0.660

Tmax=633 K

0.9182.044

1 MR PPy

Tmax=326 K

5.416

Tmax= oC

Tmax=459 K

7.342 38.492 51.250

1 MR PPy 5 %

Bismuth oxide

Tmax=346 K

6.160

Tmax= oC

Tmax=610 K

9.110

Tmax=797 K

64.460 79.730

1 MR PPy

20 % Bismuth

oxide

Tmax=347 K

0.920

Tmax=735 K

31.720

- 18.000 50.640

TGA data for Polypyrrole and Polypyrrole/Bismuth oxide conjugated

systems.

Raw Bismuth oxide starts to decompose at 538 K

with0.466 % loss

The decomposition of Polypyrrole/Bismuth oxide

occurs in multiple stages.

In Polypyrrole/Bismuth oxide, the intercalation of 20%

shows the lowest weight loss of 50.640 %

Overall, Zeolite shown the lower weight loss while

Bismuth oxide stable up to higher decompostion

temperatutre


300 320 340 360 380 400 420

0.8

1.0

1.2

1.4

1.6

1.8

2.0

The

rmal

diff

usiv

ity,

x10

-7(m

2 s-1)

Temperature (K)

1 MR

1 MR 5 % Z

1 MR 10 % Z

1 MR 15 % Z

1 MR 20 % Z

Thermal diffusivity of 1 MR Polypyrrole as a function of

Zeolite concentration at different temperature.

300 320 340 360 380 400 420

0.8

0.9

1.0

1.1

1.2

1.3

1.4

1.5

1.6

The

rmal

diff

usiv

ity,

x10

-7(m

2 s-1)

Temperature (K)

1 MR

1 MR 5 % B

1 MR 10 % B

1 MR 15% B

1 MR 20 % B

Thermal diffusivity of 1 MR Polypyrrole as a function of

Bismuth oxide concentration at different temperature.

T1 structure scattering (due to defect from blend)

T2 microvoids (vacant-site scattering)

T2T1 T1 T2

Thermal diffusivity of all samples shows a similar temperature

dependence.

For each samples there are two temperature regions were

observed T1 (slight increase of thermal diffusivity

with temperature) & T2 (thermal diffusivity fall-off or levelling-

off with temperature)

In the case of pristine Polypyrrole, it is believed that the primary

doping agent has increased the conjugation length which provide

more through-space pathways for electron to migrate.

Zeolite and Bismuth oxide have enhanced thermal properties of

Polypyrrole by forming a stronger bonding.

It is believed also that higher thermal diffusivity coming from

higher molecular weight due to larger interaction between chain

molecules. (i.e 20% of Zeolite in 1 MR Polypyrrole and 20%

Bismuth oxide 3 MR Polypyrrole)

RESULTS & DISCUSSIONA

bso

rba

nce

(a

.u)

1 MR

1 MR 5% Z

1 MR 20% Z

1 MR 5% B

1 MR 20% B

UV-VIS-NIR absorption spectra of Polypyrrole (a)

pristine 1 MR (b) doped 5 % Zeolite (c) doped 20 %

Zeolite (d) doped 5 % Bismuth oxide (e) doped 20%

Bismuth oxide.

Sample

Absorption peak position (eV)

Bipolaron Polaron

1 MR 1.393 2.061 3.450 -

1 MR 5% Zeolite 1.393 2.061 3.552 -

1 MR 20% Zeolite 1.393 2.165 3.663 -

1 MR 5% Bismuth

oxide

1.389 2.007 3.831 -

1 MR 20%

Bismuth oxide

1.396 - 3.806 4.474

Absorption peak position of Polypyrrole, Polypyrrole/Zeolite and

Polypyrrole/Bismuth oxide.

Absorption peak is the indicative of the nature charge carriers

(i.e. polaron or bipolarons).

All samples of Polypyrrole and Polypyrrole/Zeolite and

Polypyrrole/Bismuth oxide at lower doping concentration

exhibit three absorption peak which corresponds to transition

bonding to antibonding polaron and bipolaron and

interband transition of the system.

At higher concentration of Bismuth oxide another peak arise

at higher photon energy is believed associated states induced

by interaction between Polypyrrole and Bismuth oxide.

1.0 1.5 2.0 2.5 3.0 3.5 4.0

0

50

100

150

200

250

300

350

Eg = 2.147 eV

Photon energy (eV)

[F(R

h

3 MR


Kubelka-Munk transformed reflectance

spectra of pristine Polypyrrole 3 MR

conjugated systems

0

50

100

150

200

250

[F

(Rh

Eg = 2.080 eV

3 MR5% Z

0

25

50

75

100

125

150

Eg = 1.780 eV

3 MR 20% Z

1.0 1.5 2.0 2.5 3.0 3.5 4.0

0

1000

2000

3000

4000

5000

6000

Photon energy,h (eV)

[F(R

h

3 MR 5% B

Eg = 1.942 eV

1.0 1.5 2.0 2.5 3.0 3.5 4.0

0

500

1000

1500

2000

2500

3000

3500

4000

Photon energy,h (eV)

Eg = 1.911 eV

3 MR 20% B

Kubelka-Munk transformed reflectance spectra of 3 MR Polypyrrole with

(a) 5 % Zeolite (b) 10 % Zeolite, (c) 5 % Bismuth oxide, and (d) 20 %

Bismuth oxide.

DRS is a good technique in enhancing the

scattering in powder material since its more

easier, efficient and believed to be more accurate

compare as it involved cumulative of multiple

reflection.

Kubelka-Munk treatment is used by extrapolating

linear part of the plot to obatin the energy gap


Sample Energy gap, Eg (eV)

3 MR 2.147

3 MR 5% Zeolite 2.080


3 MR 5% Bismuth oxide 1.942

3 MR 20% Bismuth

oxide

1.911

Energy gap, Eg values for Polypyrrole,

Polypyrrole/Zeolite and Polypyrrole/Bismuth

oxide conjugated systems obtained from Kubelka-

Munk treatment.

It is oberved that both primary and secondary doping agents of

FeCl3, Zeolite and Bismuth oxide, band structure can be changed.

In this work, highest primary doping agent plus highest concentrations of

secondary doping agents have shown to give a small energy gap.

All the samples is suggested behavior of semiconductor

Overall with 20 % of Zeolite in 3 MR Polypyrrole have shown to have a

small energy gap that is 1.780 eV


1 MR 5 % Z

1 MR 20 % Z

1 MR

ES

R in

ten

sity

(a.u

.)

ES

R in

tens

ity (

a.u.

)

1 MR

1 MR 5 % B

1 MR 20 % B

In this work, ESR has been used as an additional technique to probe the presence of carrying species /free radical.

Pristine Polypyrrole of 1 MR shows a symmetric single-line ESR signal. This is similar to ESR signal observed at lower

concentrations of Zeolite and Bismuth oxide which suggest the polarons in the samples.

At higher concentration of secondary doping agents, the ESR signal become broader compared to pristne Polypyrrole and

lower concentrations of primary doping agents. This broad component is belived to be more easily saturated than narrow

component and this could be showing that the sample having evolution from polaron to bipolaron.

The ESR spectra of Polypyrrole doped with 5% and 20%

of Zeolite in 1 MR Polypyrrole at room temperature.

The ESR spectra of Polypyrrole doped with 5% and 20%

of Bismuth oxide in 1 MR Polypyrrole at room

temperature.


Sample g-values

3 MR 1.9951


3 MR 20% Zeolite 2.1818

3 MR 5% Bismuth oxide 1.9908

3 MR 20% Bismuth

oxide

1.9670

g-values for Polypyrrole, Polypyrrole/Zeolite and

Polypyrrole/Bismuth oxide conjugated systems obtained

from ESR measurement at room temperature.

g-value which is expressed as a function of microwave frequency and

outer magnetic field at resonance provide the information regarding the

electronic structure.

In this work, all the samples generate g-value that is closed to free

electron which is 2.002322. This observation is typical in conductive

polymer and confirmed the resonance comes from the electron

delocalized in the -system of the carbon atoms (polaron).


0 50 100 150 200 250 300

0.0

0.5

1.0

1.5

2.0

2.5

Temperature (K)

Co

nd

uct

ivity

(S

/cm

)

1 MR

1 MR 5 % Z

1 MR 20 % Z

0 50 100 150 200 250 300

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

Temperature (K)

Co

nd

uct

ivity

(S

/cm

)

1 MR

1 MR 5 % B

1 MR 20 % B

SampleElectrical Conductivity,

Scm-1

1 MR 2.000x10-2

1 MR 5% Zeolite 8.605x10-1


1 MR 5% Bismuth oxide 9.650x10-2

1 MR 20% Bismuth oxide 2.967x10-1

Experimental values of the room temperature electrical conductivity, , for

Polypyrrole, Polypyrrole/Zeolite and Polypyrrole/Bismuth oxide conjugated

systems.

The temperature dependence of conductivity for 1 MR pristine

Polypyrrole and Polypyrrole with impregnation of 5 wt% and 20

wt% of Zeolite from 20 K to 300 K.

The temperature dependence of conductivity for 1 MR pristine

Polypyrrole and Polypyrrole with impregnation of 5 wt% and 20

wt% of Bismuth oxide from 20 K to 300 K.

It is observed that the introduction of primary and secondary doping

agents, increased the conductivity of Polypyrrole.

However it is believed that at lower concentrations, the polaron occupy

random positions between the chains and cause to have low mobility.

This could be also due to midgap in the energy between polaron bands

is large which act as resistance for electron to hop from one band to

another which resulted in low conductivity.

As the doping agents in increased, more polaronare obtained and

hence a bipolaron is released. At this point, more polarons is formed

and narrower the midgap thus ease the electron to hop

conductivity increased.


0.25 0.30 0.35 0.40 0.45

-2

-1

0

1

LnS

cm-1)

T-1/4

(K-1/4

)

1 MR 5 % Z

1 MR 20 % Z

Plot of Ln versus T-1/4 of 1 MR Polypyrrole

with impregnation of 5 wt% and 20 wt% of

Zeolite.

0.20 0.25 0.30 0.35 0.40 0.45 0.50

-5

-4

-3

-2

-1

LnS

cm-1)

T-1/4

(K-1/4

)

1 MR 5 % B

1 MR 20 % B

Plot of Ln versus T-1/4 of 1 MR Polypyrrole with

impregnation of 5 wt% and 20 wt% of Bismuth oxide.

0.25 0.30 0.35 0.40 0.45 0.50

-6

-5

-4

-3

-2

1 MR

2 MR

3 MR

LnS

cm-1)

T-1/4

(K-1/4

)

Plot of Ln versus T-1/4 of 1 MR, 2 MR, 3

MR pristine Polypyrrole conjugated

systems.

Several models have been used to explain conductivity behaviour in the

polymers ( i.e. Arrhenius model).

Finally, it is found that Mott’s law for variable range hopping is

mechanism that is found suitable to describe the conductivity for

conjugated system.

After finalizing the plot of 1-D, 2-D, and 3-D VRH, it can be concluded

that 3D-VRH model is the most suitable for explaining the conduction

mechanism wherein the charge transport occurs by phonon assisted by

thermally jumps between localized site.

Polypyrrole, Polypyrrole/Zeolite and Polypyrrole/Bismuth oxide have beensuccessfully prepared usinh chemical oxidative polymerization technique.

Pristine Polypyrrole of 1 , 2 and 3 MR are mainly amorphous in naturewhile the presence of Zeolite and Bismuth oxide has introduced somedegree of crystallinity. Thus, more ordered structure is formed.

Thermal properties in terms of thermal stability and thermal diffusivity havebeen enhanced with the presence of both secondary doping agents.

The optical and electrical studies on the Polypyrrole, polypyrrole/Zeoliteand Polypyrrole/Bismuth oxide conjugated systems revealed the enhancedelectrical properties of the systems in the presence or certain amount ofZeolite and Bismuth oxide.

CONCLUSIONS

Improved thermal properties of Polypyrrole conjugated systems with thepresence of Zeolite and Bismuth oxide

Improved optical and electrical properties of Polypyrrole conjugated system through introduction of inorganic secondary doping agents.

Providing the thermal diffusivity approach for Polypyrrole, Polypyrrole/Zeoliteand Polypyrrole/Bismuth oxide conjugated systems.

RESEARCH CONTRIBUTIONS

Supervisory committee; Prof Dr Zainal Abidin Talib, Assoc. Prof Dr HalimahKamari, Prof Dr Anuar Kassim

Labmates 201, Physics & Chemistry Department, UPM

Staff, Physics & Chemistry Departments, UPM

Family and friends!

ACKNOWLEDGEMENTS

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