Polyaniline iron oxide nanocomposites were prepared by in-situ polymerization method. These nanocomposites were characterized by employing Fourier Transform Infrared (FT-IR), Scanning Electron Microscope (SEM),Thermal study by (TGA).The dc conductivity of prepared nanocomposites was measured as a function of temperature which shows the strong interaction between Polyaniline and iron oxide nanoparticles and exhibits semiconducting behavior.Finally, the sensing properties of these nanocomposites are also studied at room temperature.

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Studies on Electrical and Sensing Properties of Polyaniline / Iron Oxide (-Fe2O3) Nanocomposites. Jakeer Husain1, Chakradhar Sridhar B2, M. V. N.Ambika Prasad1* 1Department of Materials Science Gulbarga University Gulbarga.585106 Karnataka, India. 2Department of Physics Gulbarga University Gulbarga.585106 Karnataka, India. 1*Department of Materials Science Gulbarga University Gulbarga.585106 Karnataka ABSTRACT Polyaniline iron oxide nanocomposites were prepared by in-situ polymerization method. These nanocomposites were characterized by employing Fourier Transform Infrared (FT-IR), Scanning Electron Microscope (SEM),Thermal study by (TGA).The dc conductivity of prepared nanocomposites was measured as a function of temperature which shows the strong interaction between Polyaniline and iron oxide nanoparticles and exhibits semiconducting behavior.Finally, the sensing properties of these nanocomposites are also studied at room temperature. Keywords: Nanocomposites, FTIR, TGA, SEM, Conductivity,
I. INTRODUCTION
Conducting Polymer inorganic nanocomposites attracted both fundamental and practical interest because of their different chemical, biological and physical properties and application in high density magnetic recording,catalysis, magnetic resonance imaging, energy conversion etc.[1-4].Among all conducting polymer Polyaniline is one of the most promising conducting polymers due to of its ease preparation, good environmental stability, better electronic properties, low cost, density is very low and its applications in electrochromic display, electro catalysis, rechargeable batteries, sensors and biosensors [5-14].Polymer nanocompositesare also known as nanostructure materials because of improve the performance properties of the polymer by doping inorganic nanoparticles[15].Among all metal oxide nanoparticles, iron oxides have attracted technological importance and potential applications in catalysis such as magnetic storage devices, ferrofluids and other uses [16-17]. In the present work, the Polyaniline nanocomposites were synthesized by in-situ polymerization method, the synthesized nanocomposite were characterized by FT-IR,SEM, Thermal Studies like TGA and also we study the DC-conductivity and sensing properties of these prepared nanocomposites.
II. EXPERIMENTAL
2.1 SYNTHESIS OF IRON OXIDE NANOPARTICLES.
The iron oxide nanoparticles were synthesized by self-propagating low temperature combustion method, employing iron oxalate as precursor. The Precursor is prepared by dissolving equimolar quantity of ferrous ammonium sulphate and oxalic acid in distilled water. This solution stirred for ½ hour on magnetic stirrer. Yellow precipitate of iron oxalate dehydrate obtained is filtered and washed with distilled water. The prepared iron Oxalate was mixed with Polyethylene glycol (PEG) in the weight ratio 1:5. The resultant compound was placed in a crucible and heated by using electrical heater it was observed that initially PEG is melted, then frothed and finally ignited to give iron oxide as a residue, then the prepared compound was then calcinated for 2 hours to remove impurities. Finally pure iron oxide nanoparticles were obtained. 2.1 PREPARATION OF PANI/IRON OXIDE NANOCOMPOSITES. Synthesis of the PANI– iron oxide nanocomposites was carried out by in-situ polymerization method. Aniline (0.1 M) was mixed in 1 M HCl and stirred for 15 min to form aniline hydrochloride. Iron oxide nanoparticles were added in the mass fraction to the above solution with vigorous stirring in order to keep the iron oxide homogeneously suspended in the solution. To this solution , 0.1 M of ammonium persulphate, which acts as an oxidizer was slowly added drop-wise with continuous stirring at 5◦C for 4 h to completely polymerize. The precipitate was filtered, washed with deionized water, Acetone, and finally dried in an oven for 24 h to achieve a constant mass. In these way, PANI– iron oxide nanocomposites containing various weight percentage of iron oxide (10 %, 20 %, 30 %, 40 %, and 50 %) in PANI were synthesized.
III. CHARACTERIZATION.
Fourier transformed infrared spectra of these nanocomposite were recorded on Thermo Fisher
RESEARCH ARTICLE OPEN ACCESS

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ATR Nicolet model using diamond (iS5) in the range
4000-400cm-1. The morphology of the nano iron
oxide and nanocomposites in the form of powder was
investigated using SEM Model-EVO-18 Special
Edison,Zein Germany. Thermal studies were carried
out employing STA PT1600 Thermal Analyzer from
Linseis under nitrogen atmosphere with a heating rate
of 10oC/minute at a flow rate of 100
ml/min.Electrical properties of these nanocomposites
are studied by using Keithley 6514 electrometer and
sensing properties of these nanocomposites were
studied using laboratory set up.
IV. RESULT AND DISCUSSION
4.1 FT-IR ANALYSIS
422.84404.69 445.64132.83 461.07
470.94
476.38
482.89
490.52
514.37
525.62
537.77
553.76
569.29
588.32
595.16
610.71
619.20
629.99
639.43
662.23
1010.23
1083.06
1188.63
1508.27
1560.145541.45
1654.156637.50
3431.41
3676.65
3737.94
-10
0
10
20
30
40
50
60
70
80
90
100
%T
4000 3500 3000 2500 2000 1500 1000 500
Wavenumbers (cm-1)
Fig (a)pure iron oxide.
429.94419.79413.44
459.15 453.27447.35
464.20
480.95
491.97
504.53
511.32
525.09
540.77
568.26557.80
580.79
587.45
596.37
617.23
654.23636.55
667.57
676.83
694.36
701.67
741.17818.42
750.79
796.10
813.53
845.25
855.70
880.41
983.85
1105.35
1301.59
1451.23
1474.90
1540.80
1560.98
1684.14
1793.28
2332.12
2365.70
2933.71
3434.28
3489.22
3508.68
3577.18
3616.47
3629.32
3676.32
3745.49
333388787253787235893...3.02365123671
-20
-10
0
10
20
30
40
50
60
70
80
90
%T
4000 3500 3000 2500 2000 1500 1000 500
Wavenumbers (cm-1)
Fig (b)pani/iron oxide nanocomposite..
Fig.4.1 (a) & (b) shows the FTIR spectra iron oxide and pani/iron oxide nannocomposites.
Fig 4.1(a) shows FTIR spectra of pure iron oxide
nanoparticles the peaks at 3737 to 3431 cm-1 is due to
OH stretch because of absorption of water molecules,
the characteristic stretching frequencies at 1654 cm-1
is due to N-H stretch, the peaks at 1083 to 1010 cm-1
is due to C-H bending the peaks from 657 to 424 cm-
1is due to metallic stretch.
Fig 4.1(b) shows the IR spectra of Pani/iron oxide
nanocomposite the characteristic stretching
frequency was observed at 3745 to 3434 cm-1 is due

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to O-H stretching ,the peaks at 2933 to 2332 cm-1 is due to C-H stretch, the peaks at 1793 and 1684 cm-1 is due to C=O stretch ,the peaks 1560 to 1451 cm-1 is due to C-H bending ,the peaks at 880 to 676cm-1 is due to Alkene=C-H bending and the peaks at 540 to 429 cm-1 is due to metallic stretch .By comparing IR spectra of pani and pani/iron oxide nanocomposite, it is observed that in the composite the characteristic stretching frequencies are shifted towards higher frequencies side which may attribute due to Vander walls kinds of interaction between iron oxide and pani chain. 4.2 SCANNING ELECTRON MICROSCOPY Fig (a)Pure Iron oxide Fig (b)Pani/iron oxide nanocomposite. Figure 4.2 Scanning electronic micrograph (SEM) image of Pure Iron oxide and Pani/Iron oxide nanocomposite.
Figure 4.2(a)&(b) shows the micrograph of iron oxide and Pani/Iron oxide nanocomposites It is seen clearly from the SEM micrograph of iron oxide, it has cluster of spherical shaped particles. figure 4. 2.(b) Shows the micrograph of iron oxide nanocomposite it is observed that the iron oxide nanocomposites are cluster like structure. The presence of such sharp crystal of iron oxide nanoparticles has a strong influence on various electrical parameters of these nanocomposites.

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4.3 Thermal analysis
0 100 200 300 400 500 600 700 800 900
90
92
94
96
98
100
Weight loss
Temprature
Pani/iron oxide nanocomposites
Figure 4.3 shows the TGA graph of 50wt% Pani/Iron oxide nanocomposite
Figure 3 shows the thermo graph of Pani/Iron
oxide nanocomposites. the thermograph shows two
weight losses as seen in fig 3. the first weight loss
corresponds the evaporation of water molecules from
the prepared nanocomposites.The second weight loss
is due to the decomposition of organic moiety.
4.4 DC CONDUCTIVITY STUDIES.
40 60 80 100 120 140 160 180 200
5.0x10-6
1.0x10-5
1.5x10-5
2.0x10-5
2.5x10-5

dc
(S/cm)
Temprature (
o
C)
Pani
10wt%
20wt%
30wt%
40wt%
50wt%
Fig.4 shows the dc conductivity of pani/iron oxide nanocomposites..
Fig 4 shows the DC conductivity of Polyaniline
and Pani/iron oxide nanocomposite of different
weight percentage as a function of temperature range
from 30 to 180 0c. The DC conductivity remains
almost constant up to 1200c and thereafter it increases
up to1800c, which is the characteristic behavior of
semiconducting materials. The conductivity increases
with an increase in temperatures due to the flow of
ions from one localized state to another and It is also
suggested here that the thermal curling effects of the
chain alignment of the Polyaniline leads to the
increase in conjugation length and that brings about
the increase of conductivity.
The conductivity varies directly with the,
obeying an expression of the following form:
σ (T) = σ0exp [-T0/T)1/4]
Where: σ is the conductivity, T is the temperature and
σ0 is the conductivity at characteristic temperature
T0.
4.5 Sensing studies

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-200 0 200 400 600 800 1000 1200 1400 1600 1800 2000
0.0
5.0x102
1.0x103
1.5x103
2.0x103
2.5x103
3.0x103
3.5x103
Sensitivity%
Time in seconds
pani
10wt%
20wt%
30wt%
40wt%
50wt%
Fig.5. Variation of sensitivity against LPG
Fig (5) shows sensitivity vs time for Polyaniline
/Iron oxide nanocomposites it is seen that the
Pani/iron oxide nanocomposites shows better
sensitivity to gas vapor compared to pure Polyaniline
and other nanocomposites such as (10,20,30,40 wt%)
50wt% nanocomposites shows height sensitivity this
is due to the strong interaction between the
Polyaniline and iron oxide nanoparticles. In the case
of pure Polyaniline and 10wt% of nanocomposites
sensitivity is very low because of lower surface are
V. CONCLUSIONS:
Polyaniline Iron oxide nanocomposites were prepared
by in-situ polymerization method, the FT-IR spectra
conforms the formation of pani/iron oxide
nanocomposites. The SEM image shows the presence
of iron oxide nanoparticles which are uniformly
distributed throughout the nanocomposite sample.
The presence of iron oxide nanoparticle in Pani
nanocomposites influences on electrical and Sensing
parameter such as conductivity and Sensitivity of
these nanocomposites. The DC conductivity studied
shows the prepared nanocomposites exhibits typical
semiconductor behavior. It is conclude that this Pani
iron oxide nanocomposites is one of the promising
materials for the potential applications.
VI. ACKNOWLEDGEMENTS:
The author Jakeer Husain gratefully
acknowledges the financial support from DST
INSPIRE Program.
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