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10/30/2010
1
University of University of SulaimaniSulaimani
College of ScienceCollege of Science
Physics DepartmentPhysics Department
Ionic Conduction in Ionic Conduction in Polymers CompositePolymers CompositePolymers CompositePolymers Composite
Omed Omed GhGh. Abdullah. Abdullah
STUDY THE EFFECT OF TEMPERATURE AND FREQUENCY ON THE DIELECTRIC PROPERTIES OF
SOME COMMERCIAL POLYMERS
A THESIS SUBMITTED TO THE COUNCIL OF
COLLEGE OF SCIENCE UNIVERSITY OF SULAIMANI
STUDY THE EFFECT OF TEMPERATURE AND FREQUENCY ON THE DIELECTRIC PROPERTIES OF
SOME COMMERCIAL POLYMERS
A THESIS SUBMITTED TO THE COUNCIL OF
COLLEGE OF SCIENCE UNIVERSITY OF SULAIMANIIN PARTIAL FULFILMENT OF REQUIREMENTS FOR
THE DEGREE OF MASTER OF SCIENCE IN PHYSICS
BYSHUJAH‐ALDEEN BAKIR AZIZ
B.Sc. IN PHYSICS‐2003(Sulaimani University)
IN PARTIAL FULFILMENT OF REQUIREMENTS FOR THE DEGREE OF MASTER OF
SCIENCE IN PHYSICS
BYSHUJAH‐ALDEEN BAKIR AZIZ
B.Sc. IN PHYSICS‐2003(Sulaimani University)
UNDER SUPERVISION OF:Prof. Dr. HAMEED MAJID AHMED
September Gelawezh2007 2707
UNDER SUPERVISION OF:Prof. Dr. HAMEED MAJID AHMED
September Gelawezh2007 2707
10/30/2010
2
OPTICAL AND ELECTRICAL PROPERTIES OF SEMICONDUCTING OXIDE GLASSES
A THESISSUBMITTED TO THE COUNCIL OF
COLLEGE OF SCIENCE UNIVERSITY OF SULAIMANIIN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR
OPTICAL AND ELECTRICAL PROPERTIES OF SEMICONDUCTING OXIDE GLASSES
A THESISSUBMITTED TO THE COUNCIL OF
COLLEGE OF SCIENCE UNIVERSITY OF SULAIMANIIN PARTIAL FULFILLMENT OF THE REQUIREMENTS FORIN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY IN PHYSICS
BYDANA ABDULLA TAHIR
(M. Sc.) in physics Salahaddin University‐1995
IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY IN PHYSICS
BYDANA ABDULLA TAHIR
(M. Sc.) in physics Salahaddin University‐1995
UNDER SUPERVISION OF:MANAF ABD HASSAN AHMAD AL‐ANIAssistant Professor Lecturer
September September GalawezhGalawezh2007 2007 2707 2707
UNDER SUPERVISION OF:MANAF ABD HASSAN AHMAD AL‐ANIAssistant Professor Lecturer
September September GalawezhGalawezh2007 2007 2707 2707
Dielectric analysis of Polystyrene Dielectric analysis of Polystyrene polymer filmpolymer film
Dana A. Tahir, Omed Gh. Abdullah, and Shuja‐Aldeen B. AzizD f Ph i C ll f S i S l i i U i iDepartment of Physics, College of Science, Sulaimani University
AbstractIn this work an attempt has been made to study the various dielectric
parameters of polystyrene film. The dielectric constant , dielectric loss andloss tangent have been determined in the frequency range (1‐000)KHz atdifferent temperatures. The frequency dependent conductivity was alsomeasured to characterize the polymer. The complex impedance plot (cole‐cole plot) was used to calculate the static dielectric constant , infinitely largecole plot) was used to calculate the static dielectric constant , infinitely largefrequency dielectric constant and relaxation times. Finally the results areanalyzed in terms of different parameters.
Key words:Key words: polymer film, dielectric constant, dielectric loss, relaxation, activation polymer film, dielectric constant, dielectric loss, relaxation, activation energyenergy
10/30/2010
3
Optical and Electrical Properties of Optical and Electrical Properties of PolyvinylPolyvinyl‐‐chloride (PVC) filmschloride (PVC) films
Omed Gh. Abdullah, Dana A. Tahir, and Shuja‐Aldeen B. AzizDepartment of Physics College of Science Sulaimani UniversityDepartment of Physics, College of Science, Sulaimani University
AbstractThe optical properties of the polyvinyl‐chloride thin films were studied which
include their absorbance, transmittance, reflectance spectra, band gap, and refractiveindex, before and after annealing at T=75oC for 24hrs. The films were found to exhibithigh transmittance, low absorbance and low reflectance in the visible, and nearinfrared region up to 1100nm. However, the absorbance of the films was found to behigh in the ultra violet region with peak around 306nm. The dielectric constant,dielectric loss, and ac conductivity of polyvinyl‐chloride were obtained at differentf i d h i l l h h ’ d ”frequencies and temperatures. The experimental results show that ’ and ”decreased with increasing frequency, which indicates that the major contribution tothe polarization comes from orientation polarization. The value of ’ increased withincreasing temperature, which is due to great freedom of movement of the dipolemolecular chains at high temperature.
Key words: thin film, optical properties, electrical properties, complex permittivityKey words: thin film, optical properties, electrical properties, complex permittivity..
Debye behaviorDebye behavior
0.4
0.45T=25 C0.4
0.45T=25 C
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
Die
lect
ric
loss
T=50 C
T=75 C
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
Die
lect
ric
loss
T=50 C
T=75 C
Cole‐Cole plot for Polystyrene at different temperatures.
1.6 1.8 2 2.2 2.4 2.6
Dielectric constant
1.6 1.8 2 2.2 2.4 2.6
Dielectric constant
10/30/2010
4
International Journal of Materials ScienceISSN 0973‐4589 Volume 5, Number 4 (2010), pp. 537–545© Research India Publicationshttp://www.ripublication.com/ijoms.htm
Physical Properties of Pure and Copper Oxide DopedPolystyrene FilmsPolystyrene Films
Omed Gh. Abdullah and Dana S. MuhammadDepartment of Physics, College of Science, University of Sulaimani ‐ Iraq
AbstractAbstract
The UV/VIS optical absorption for difference compositions copper oxide dopedpolystyrene thin films were studied in the wavelength 200‐1000 nm. It was found thatthe optical absorption is due to direct allowed transitions, and the energy gaps showsnonlinear behavior with copper oxide concentration, optical energy gap showed anonlinear behavior with copper oxide concentration, optical energy gap showed adecreasing trend with increased dopant concentration up to 10% of the dopant, forfurther increase in dopant concentration this value started increasing again due tosegregation effects. The annealing of the samples at temperature 90oC for 4 hr, causedthe decrease in energy gaps. The studies of the real and imaginary parts of thedielectric constants showed that they are also affected by copper oxide concentration.
Key words: optical properties, polymer composite, doping, complex dielectric constant.
10/30/2010
5
Absorption SpectrumAbsorption Spectrum
0.45
0.5
PSPS--0%CuO0%CuO
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
0.4A
bso
rban
cePSPS--5%CuO5%CuO
PSPS--10%CuO10%CuO
PSPS--15%CuO15%CuO
PSPS--2020%CuO%CuO
Optical absorption for PS with different CuO content, as a function of wavelength.
265 285 305 325 345 365
Wavelength (nm)
Optical Band GapsOptical Band Gaps
0 2
0.254.49
0
0.05
0.1
0.15
0.2
4.46
4.47
4.48
0 5 10 15 20 25
EtE
opt
Optical energy gap of direct allowed transition, and tail localized state energy against copper oxide concentration, of pure and doped polymer film before (solid line), and after annealing
(dashed line).
0 5 10 15 20 25
CuO concentration %
10/30/2010
6
Effect of Zirconia concentration on optical properties of Polystyrene films
Omed Gh. Abdullah and Dlear R. SaberDepartment of Physics, College of Science, University of Sulaimani ‐ Iraq
AbstractAbstractOptical properties of prepared Polystyrene (PS) films with different filling levels of
Zirconia have been investigated in the visible and ultraviolent wavelength regions. Itwas found that the optical absorption is due to direct‐allowed transitions, and theenergy gaps decrease with increasing Zirconia content for all transitions, while thewidth of the tail localized states increase with increasing Zirconia content. The bandgap of all films shows to be decrease after thermal treatment. The optical constantsrefractive index n, extinction coefficient K, have been also calculated. The refractiveindex increased in the composite samples as compared with the pure PS samplep p p p pprepared by the same method.
Key words: polymer, optical properties, filler, extinction coefficient, annealing. PACS: 78.20.Ci
Refractive indexRefractive index
2 5
3
ex) PSPS‐‐20% ZrO20% ZrO22
1
1.5
2
2.5
250 350 450 550 650 750 850 950 1050
n (
Ref
rect
ive
Ind
e
PSPS‐‐0% ZrO0% ZrO22
PSPS‐‐5% ZrO5% ZrO22
PSPS‐‐10% ZrO10% ZrO22
PSPS‐‐15% ZrO15% ZrO22
Refractive index as a function of wavelength for PS for different Zirconia content.
250 350 450 550 650 750 850 950 1050
Wavelength (nm)
10/30/2010
7
Refractive indexRefractive index
2 5
3
ex) PSPS‐‐20% ZrO20% ZrO22
Since the refractive index of this composite was controllable
b
1
1.5
2
2.5
250 350 450 550 650 750 850 950 1050
n (
Ref
rect
ive
Ind
e
PSPS‐‐0% ZrO0% ZrO22
PSPS‐‐5% ZrO5% ZrO22
PSPS‐‐10% ZrO10% ZrO22
PSPS‐‐15% ZrO15% ZrO22
it can be used to fabricate waveguides with the desired refractive index contrast
Refractive index as a function of wavelength for PS for different Zirconia content.
250 350 450 550 650 750 850 950 1050
Wavelength (nm)
contrast between the core and the cladding
Optical band GapOptical band Gap
0.3
0.35
0.4
4.46
4.48
0
0.05
0.1
0.15
0.2
0.25
0.3
4 36
4.38
4.4
4.42
4.44
E t(eV)
E opt(eV)
The optical gap, and tail localized state as a function of Zirconiacontent, before (solid line) and after annealing (dashed line).
04.36
0 5 10 15 20 25
ZrO2 %
10/30/2010
8
Variation of Optical Band Gap Width of PVA films Doped with Aluminum Iodide
Omed Gh. Abdullah and Sarkawt Abubakr HussenDepartment of Physics, College of Science, University of Sulaimani ‐ Iraq
AbstractAbstractPolymer composite of polyvinyl alcohol (PVA), Aluminum Iodide have been prepared by solution cast
method for different doping concentrations The absorption of pure and doped films have beenmethod for different doping concentrations. The absorption of pure and doped films have beeninvestigated in the visible and ultraviolent wavelength regions. It was found that the optical absorptionis due to direct and indirect transitions, and the optical energy gaps values shifted to lower energies onAluminum Iodide doping concentration for all transitions, while the band edge width of the tail localizedstates increase with increasing Aluminum Iodide concentration. The band gap of all films shows to bedecrease after thermal treatment. The optical constants refractive index n, extinction coefficient K, thecomplex dielectric constant have been also calculated. The dielectric constant increased in thecomposite samples as compared with the pure PVA sample prepared by the same method.
Key words: polymer composite, optical properties, doping, complex dielectric constant.
Absorption SpectrumAbsorption Spectrum
0 35
0.4
0.45
a.u
.) PVA-0%AlI
PVA 5%AlI
PVAPVA‐‐0%AlI0%AlI33PVAPVA 5%AlI5%AlI
0
0.05
0.1
0.15
0.2
0.25
0.3
0.35
200 220 240 260 280 300
Ab
sorb
ance
(a PVA-5%AlI
PVA-10%AlI
PVA-15%AlI
PVA-20%AlI
PVAPVA‐‐5%AlI5%AlI33PVAPVA‐‐10%AlI10%AlI33PVAPVA‐‐15%AlI15%AlI33PVAPVA‐‐20%AlI20%AlI33
Optical absorption as a function of wavelength for PVA at different Aluminum Iodide content.
200 220 240 260 280 300
Wavelength (nm)
10/30/2010
9
Direct Optical Band GapsDirect Optical Band Gaps
80
90
10004 )
PVAPVA--00%AlI%AlI
PVAPVA--5%AlI5%AlI
0
10
20
30
40
50
60
70
5 5.25 5.5 5.75 6 6.25 6.5
h
v2
(1
0 PVAPVA--5%AlI5%AlI
PVAPVA--10%AlI10%AlI
PVAPVA--15%AlI15%AlI
PVAPVA--20%AlI20%AlI
Direct optical band gaps for PVA with Aluminum Iodide content.
hv (eV)
Indirect Optical Band GapsIndirect Optical Band Gaps
35
40PVAPVA--0%AlI0%AlI
PVAPVA--5%AlI5%AlI
0
5
10
15
20
25
30
5 5.25 5.5 5.75 6 6.25 6.5
h
v1/
2 PVAPVA--1010%AlI%AlI
PVAPVA--15%AlI15%AlI
PVAPVA--20%AlI20%AlI
Indirect optical band gaps of PVA with Aluminum Iodide content.
5 5.25 5.5 5.75 6 6.25 6.5
hv (eV)
10/30/2010
10
Band tails Band tails of localized statesof localized states
5
5.5
6PVAPVA--0%AlI40%AlI4
PVAPVA--55%AlI%AlI44
PVAPVA 10%AlI410%AlI4
1
1.5
2
2.5
3
3.5
4
4.5
5
5.1 5.15 5.2 5.25 5.3 5.35 5.4
ln
PVAPVA--10%AlI410%AlI4
PVAPVA--15%AlI415%AlI4
PVAPVA--20%AlI420%AlI4
Natural logarithm of absorption coefficient as a function of photon energy.
5.1 5.15 5.2 5.25 5.3 5.35 5.4
hv (eV)
Dielectric properties of Polyester reinforced with Carbon black particles
Omed Gh. Abdullah, Gelas M. Jamal, Dana A. Tahir, and Salah Raza SaeedD t t f Ph i C ll f S i U i it f S l i i IDepartment of Physics, College of Science, University of Sulaimani ‐ Iraq
AbstractAbstractDielectric constant and conductivity of Polyester doped with carbon black
are investigated in the frequency range (0.5‐1000) KHz and within thetemperature range (28‐80)oC. Dielectric permittivity and loss tangent arefound to be decrease with increasing frequency and increase with increasingtemperature. The ac conductivity is found to be frequency‐independent forlow frequency however vary with frequency as ws, beyond a critical value. Theq y y q y , yfrequency exponential factor was estimated and it was found to vary between0.63 and 0.77, indicating a dominant hopping process at low temperatures.From the temperature dependence of dc conductivity, the increase ofactivation energy was observed with carbon black concentrations.
Key words: ac conductivity, polyester, carbon black, dielectric constant.
10/30/2010
11
Complex Dielectric Constant
’Permittivity or Dielectric
At high frequencies dipoles cannot return rapidly enough - charging cannot occur/dielectric constant is lowAt low frequencies
dipoles can align --
log f
”fmax
Dielectric Constant Frequency at
which dipoles respond to the field
At high frequencies, dipoles cannot move rapidly enough to respond –losses
Losses
dipoles can align dielectric constantis high
log f
lossesare low
’ and ” as a functionof frequency – at constant temperature
Permanent dipoles FOLLOW variations in the AC field –hence current and voltage out of phase – losses low
Frequency at which permittivity drops and losses increase is where the polymer is said to show dispersionFrequency at which permittivity drops and losses increase is where the polymer is said to show dispersion
acac conductivity virus concentrationconductivity virus concentration
60
70t=26 C
t=40 C
t 60 C
10
20
30
40
50
ac (s/m 10‐6)
t=60 C
t=80 C
ac conductivity dependence on black carbon concentration at different temperatures
0
0 5 10 15 20
BC % Concentration
10/30/2010
12
acac conductivity virus frequencyconductivity virus frequency
-4.5
-4
T=26 C
T=40 C
-6
-5.5
-5
4.5lo
g(
ac) T=60 C
T=80 C
,
Dependence of frequency on the ac conductivity at different temperatures of Polyester film doped with of Carbon black
-6.5
3.25 3.75 4.25 4.75 5.25 5.75 6.25 6.75
log(w)
,
10/30/2010
13
acac conductivity virus frequencyconductivity virus frequency
,
The variation of the exponent with temperature gives information on the specific mechanism involved. The exponential factor was calculated from slope of Fig. at high frequency, and it was found to be . , . , . , and . for the temperature
, , , respectively; indicating that is weakly decreasing function of temperature. This could be attributed that g pat higher temperature, high mobility of free charges make them more frequency independent conductivity which as a result increases conductivity.
acac conductivity virus temperatureconductivity virus temperature
‐5.50
‐5.00
‐8.50
‐8.00
‐7.50
‐7.00
‐6.50
‐6.00
log(dc)
0%CB
6%CB
12%CB
18%CB
Semilogarithmic plots of dc conductivity against reciprocal of temperature at different Carbon black concentrations
‐9.00
2.8 2.9 3 3.1 3.2 3.3 3.4
1000/T (1/K)
18%CB
10/30/2010
14
acac conductivity virus temperatureconductivity virus temperature
From the slope of parallel straight line with negative slope,the activation energy is calculated. The values of isessentially dependent of black carbon concentrations and of avalue . , . , . , . for the , , , %CB, respectively. It was clear that activation energy valueincreases with increasing the CB content. The addition of CBincreases with increasing the CB content. The addition of CBto Polyester host enhances the electrical conduction ofPolyester host due to the electronic and impurity contributionsarising from the CB.
OCH2CH2OC(CH2)CO
O O nCH2CH2CO
On
ConclusionConclusion
The main observation in this study worth tobe mentioned relates to the relative value ofbe mentioned relates to the relative value ofelectrical conductivity versus the carbon blackcontents; it was observed that even lowamount of carbon black able to maximize theconductivity of the composite up to threeorders of magnitude, we conclude thatorders of magnitude, we conclude thatpolyester carbon black composite is a goodcandidate and alternative way for obtainingconducting organic composites at low cost.
10/30/2010
15
Optical absorption of polyvinyl alcohol films doped with Nickel Chloride
Omed Gh. Abdullah, and Dlear R. SaberDepartment of Physics, College of Science, University of Sulaimani ‐ Iraq
AbstractAbstractFilms of pure and doped Polyvinyl alcohol (PVA) with different concentration of
Nickel Chloride (NiCl2) were prepared using the casting technique, in order toinvestigate effect of NiCl2 additions on the optical properties of PVA host. Thedispersion studies of pure PVA film and PVA films doped with NiCl2 were investigatedusing complex refractive index in the wavelength range 190‐1100 nm. The absorptionspectral analysis showed that the optical band was from the direct and indirectallowed optical transitions. The optical band gap of the films decreases withincreasing NiCl2 contents, while the Urbach energy called the width of localized statesincreasing NiCl2 contents, while the Urbach energy called the width of localized statesin the optical band gap decreases from 0.7414 to 0.1891 eV. Consequently, the opticalconstants and optical band gap of the samples change with the annealingtemperatures.
Key words: absorbance, PVA, dopand, optical band gap.
UV/VISUV/VIS Optical Absorption SpectraOptical Absorption Spectra
0 04
0.05
PVA-0%NiCl2
PVA 5%NiCl2
PVA‐0%NiCl2PVA 5%NiCl
0
0.01
0.02
0.03
0.04
Ab
sorb
ance
(a
.u.) PVA-5%NiCl2
PVA-10%NiCl2
PVA-15%NiCl2
PVA‐5%NiCl2PVA‐10%NiCl2PVA‐15%NiCl2
The optical absorption coefficient spectrum of PVA‐NiCl2composites
190 240 290 340 390 440 490
Wavelength (nm)
10/30/2010
16
UV/VISUV/VIS Optical Absorption SpectraOptical Absorption Spectra
0 04
0.05
PVA-0%NiCl2
PVA 5%NiCl2
PVA‐0%NiCl2PVA 5%NiCl
0
0.01
0.02
0.03
0.04A
bso
rban
ce (
a.u
.) PVA-5%NiCl2
PVA-10%NiCl2
PVA-15%NiCl2
PVA‐5%NiCl2PVA‐10%NiCl2PVA‐15%NiCl2
The optical absorption coefficient spectrum of PVA‐NiCl2composites
190 240 290 340 390 440 490
Wavelength (nm)
UV/VISUV/VIS Optical Absorption SpectraOptical Absorption Spectra
0 04
0.05
PVA-0%NiCl2
PVA 5%NiCl2
PVA‐0%NiCl2PVA 5%NiCl
0
0.01
0.02
0.03
0.04
Ab
sorb
ance
(a
.u.) PVA-5%NiCl2
PVA-10%NiCl2
PVA-15%NiCl2
PVA‐5%NiCl2PVA‐10%NiCl2PVA‐15%NiCl2
The optical absorption coefficient spectrum of PVA‐NiCl2composites
190 240 290 340 390 440 490
Wavelength (nm)
10/30/2010
17
TwoTwo conditionsconditions toto becomebecome conductiveconductive::1‐The first condition for this is that the polymer consists of
alternating single and double bonds, called conjugated doublebonds.
In conjugation, 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 stronglylocalised “pi” (π) bond which is weaker.
10/30/2010
18
2-The second condition is that the plastic has to be disturbed -either by removing electrons from (oxidation), or insertingthem into (reduction) the material The process is known as
TwoTwo conditionsconditions toto becomebecome conductiveconductive::
them into (reduction), the material. The process is known as
Doping.There are two types of doping:
1-oxidation with halogen (or p-doping).
32
3ICHI
xCH nn
2- Reduction with alkali metal (called n-doping).
xNaCHxNaCH xnn
2
FactorsFactors thatthat affectaffect thethe conductivityconductivity
11‐‐Denesity of Denesity of chargecharge carrierscarriers..
22‐‐ ThierThier mobilitymobility..
33‐‐The The directiondirection..
44‐‐ PresencePresence of doping of doping materialsmaterials ((additivesadditives thatthatfacilitatefacilitate thethe polymerpolymer conductivityconductivity))
55‐‐Temperature.Temperature.
10/30/2010
19
Electrical characterization of polyvinyl alcohol films doped with sodium iodide
Omed Gh. AbdullahDepartment of Physics, College of Science, University of Sulaimani ‐ Iraq
AbstractAbstractPolyvinyl alcohol (PVA) films doped with sodium iodide up to (30wt%) were
prepared in order to investigate the effect of sodium iodide additions on the electricalproperties of PVA host. The dielectric permittivity, dielectric loss, electric modulus andac conductivity were studied in the frequency range 20KHZ‐1MHz and in temperaturerange 300‐350 K. Upon increasing the contents of sodium iodide an increase in thedielectric permittivity, dielectric loss and ac conductivity of PVA host are observed. Theac conductivity is found to obey power law Bws. The frequency exponential factor swas estimated and it was found to vary between 0.92 and 0.34, dependence onwas estimated and it was found to vary between 0.92 and 0.34, dependence onsodium iodide contents. From the temperature dependence of ac conductivity, theincrease of activation energy was observed with dopant concentration.
Key words: ac conductivity, electric modulus, complex dielectric constants, doping.
acac conductivity virus frequencyconductivity virus frequency
90
100
0
10
20
30
40
50
60
70
80
ac
s/m
(10
-6)
PVA-0%NaI
PVA-10%NaI
PVA-20%NaI
PVA-30%NaI
CC CC
HH OHOH
HH HH
nn
Variation of ac conductivity with frequency for PVA‐NaIcomposites
0
0 200 400 600 800 1000
f (KHz)
10/30/2010
20
Activation EnergyActivation Energy
-1
0PVA-0%NaI
PVA-10%NaI
-6
-5
-4
-3
-2lo
g(
dc)
PVA 10%NaI
PVA-20%NaI
PVA-30%NaI
Semilogarithmic plots of dc conductivity against reciprocal of temperature at different NaI concentrations
-6
2.8 2.9 3 3.1 3.2 3.3 3.4
1000/T (K-1)
Activation EnergyActivation Energy
Table(1): Values of activation energy (Ea) and the exponential factor (s) for PVA‐NaI composites.
Table(1): Values of activation energy (Ea) and the exponential factor (s) for PVA‐NaI composites.
Samples ( )0% . 0.92
,
10% . 0.87 20% . 0.6330% . 0.34
10/30/2010
21
Electric ModulusElectric Modulus
0 025
0.03
0.035
0.04
0.045
0.05
M"
(a)
0 025
0.03
0.035
0.04
0.045
0.05
M"
(b)
0
0.005
0.01
0.015
0.02
0.025
0 0.1 0.2 0.3 0.4
M'
T=300 K
T=310 K
T=320 K
T=330 K
T=340 K
T=350 K
0
0.005
0.01
0.015
0.02
0.025
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35
M'
T=300 KT=310 KT=320 KT=330 KT=340 KT=350 K
0.04
0.05
0.06
0.07
M"
(c)
0.06
0.08
0.1
0.12
M"
T 300 K
(d)
Argand plots of (a) pure PVA, (b) 10 wt%, (c) 20 wt% and
(d) 30 wt% NaI‐PVA composites.
Argand plots of (a) pure PVA, (b) 10 wt%, (c) 20 wt% and
(d) 30 wt% NaI‐PVA composites.
0
0.01
0.02
0.03
0 0.05 0.1 0.15 0.2 0.25 0.3 0.35
M'
T=300 K
T=310 K
T=320 K
T=330 K
T=340 K
T=350 K
0
0.02
0.04
0 0.1 0.2 0.3 0.4
M'
T=300 K
T=310 K
T=320 K
T=330 K
T=340 K
T=350 K
10/30/2010
22