Enhancement of electroconductivity of polyaniline/graphene oxidenanocomposites through in situ emulsion polymerization
Syed Muhammad Imran • YouNa Kim •
Godlisten N. Shao • Manwar Hussain •
Yong-ho Choa • Hee Taik Kim
Received: 18 July 2013 / Accepted: 9 October 2013
� Springer Science+Business Media New York 2013
Abstract The present study introduces a systematic
approach to disperse graphene oxide (GO) during emulsion
polymerization (EP) of Polyaniline (PANI) to form nano-
composites with improved electrical conductivities. PANI/
GO samples were fabricated by loading different weight
percents (wt%) of GO through modified in situ EP of the
aniline monomer. The polymerization process was carried
out in the presence of a functionalized protonic acid such as
dodecyl benzene sulfonic acid, which acts both as an
emulsifier and protonating agent. The microstructure of
the PANI/GO nanocomposites was studied by scanning
electron microscopy, transmission electron microscopy,
X-ray diffraction, UV–Vis spectrometry, Fourier transform
infrared, differential thermal, and thermogravimetric anal-
yses. The formed nanocomposites exhibited superior mor-
phology and thermal stability. Meanwhile, the electrical
conductivities of the nanocomposite pellets pressed at
different applied pressures were determined using the four-
probe analyzer. It was observed that the addition of GO
was an essential component to improving the thermal
stability and electrical conductivities of the PANI/GO
nanocomposites. The electrical conductivities of the
nanocomposites were considerably enhanced as compared
to those of the individual PANI samples pressed at the
same pressures. An enhanced conductivity of 474 S/m was
observed at 5 wt% GO loading and an applied pressure of 6
t. Therefore, PANI/GO composites with desirable proper-
ties for various semiconductor applications can be obtained
by in situ addition of GO during the polymerization
process.
Introduction
Advancements in semiconductor technologies prompt
many researchers to fabricate superior materials with
desirable properties for that purpose. Predominantly, con-
ductive polymers have gained a lot of attention due to their
unique morphology and structure suitable for different
technological applications. These materials are particularly
used for electronic applications such as sensors, light-
emitting diodes, and solar cells. Recently, Polyaniline
(PANI) has emerged as one of the most promising con-
ducting polymers for industrial applications due to its
desirable electrical, electrochemical, and optical properties,
and excellent environmental and thermal stability [1].
Generally, PANI is solely unique since its electrical
properties can reversibly be controlled by changing the
oxidation state of the main chain and protonation of the
imine nitrogen atoms.
Various nanofillers can be added in PANI matrix to
synthesis nanocomposites in order to gain composites with
superior thermal, electrical, and mechanical properties.
Particularly, a new type of functional nanocomposite based
on graphene oxide (GO)-reinforced PANI has extensively
been studied to produce materials with desired electro-
chemical properties. GO is a potential nanofiller due to its
suitable mechanical, structural, and thermal properties in
comparison with conventional nanofillers [2, 3]. However,
many researchers are carrying out extensive studies to
S. M. Imran � Y. Kim � G. N. Shao � M. Hussain � Y. Choa �H. T. Kim (&)
Department of Fusion Chemical Engineering, College of
Engineering Sciences, Hanyang University, Ansan,
Gyeonggi 426-791, Republic of Korea
e-mail: [email protected]; [email protected]
G. N. Shao
Department of Chemistry, Mkwawa College, University of Dar
es Salaam, Iringa, United Republic of Tanzania
123
J Mater Sci
DOI 10.1007/s10853-013-7816-5
investigate the structure of GO. Wilson et al. [4] using
TEM imaging and diffraction demonstrated that GO retains
strong crystalline order. Rourke and Thomas et al. [5, 6]
showed that GO produced by the Hummers method is
composed of functionalized graphene sheets decorated by
strongly bound oxidative debris, which acts as a stabilizer
for the GO aqueous suspensions. Therefore, the chemical
stability, easy availability, low cost of precursor (natural
graphite), and the possibility of being produced in large-
scale quantities are the main attributes making GO more
preferable than other types of fillers such as carbon nano-
tubes (CNTs) and carbon nanofibers. It can be an appro-
priate substitute for CNTs and does not require helicity
control. The GO can readily be dispersed in water due to its
strong hydrophilic properties. The tunable polar oxygen-
containing groups on GO make strong interfacial interac-
tions with polar molecules and polymers resulting in
intercalated or exfoliated GO-based polymer nanocom-
posites [7–9]. Moreover, the thermal stability of the
nanocomposites improves to a great extent with the addi-
tion of GO [10–12].
The exfoliated GO possesses a large surface area and
could form stronger interactions with the PANI matrix than
that of tubular CNTs resulting in the superior thermal and
electrical properties [13]. Many researchers [14–16] have
reported that PANI/GO nanocomposites can endorse better
electrochemical capacitance and charge–discharge cyclic
stability than its individual components. During in situ
synthesis of nanocomposites, the aniline is chemically
polymerized in an acidic aqueous medium in the presence
of an oxidant [17]. The obtained polymer is irregular, in
powder form, and often with low degrees of crystallinity
and molecular orientation, which is associated with modest
values of the electrical conductivity of the as-polymerized
polymer [18]. The conductivity of PANI depends on the
ability to transport charge carriers along the polymer
backbone and for the carriers to hop between polymer
chains. Zhang [19] and Xia et al. [20] described that the
conductivity of PANI is a sum of the inter-chain and intra-
chain conductivity. In case of coil-like conformation of
PANI chains, the intra-chain conductivity increases, while
the high crystallinity of PANI will result in the increase of
inter-chain conductivity.
Yu et al. [12] synthesized PANI/Graphite nanocom-
posites by the chemical oxidation method in the presence
of perchloric acid (a very strong acid) to yield nanocom-
posites with modest values of electrical conductivities.
Subsequently, Zhao et al. [13] reported the synthesis of
PANI/GO nanocomposites through in situ polymerization
of aniline using hydrochloric acid. The maximum electrical
conductivity of the nanocomposites was 751 S/m for the
nanocomposites with GO contents [40 wt%. In both cases,
strong acids were used in the polymerization process
leading to the formation of nanocomposites with low
crystallinity.
Herein, we synthesized highly crystalline PANI/GO
nanocomposites by using modified in situ emulsion poly-
merization (EP) of the aniline monomer. Aniline was
polymerized in an emulsion of water and xylene. The
polymerization process for the synthesis of PANI/GO
nanocomposites was carried out in the presence of a
functionalized protonic acid, such as dodecyl benzene
sulfonic acid (DBSA), which acts simultaneously as an
emulsifier and protonating agent for the resulting PANI.
The thermal stability of the nanocomposites with different
GO wt% was also examined. The relationship among
conductivities, GO content, and pressing pressure was
studied by forming pellets of PANI/GO nanocomposites at
different pressing pressures and determining their electrical
conductivities. The electrical conductivities obtained in the
present study were exquisitely compared to those available
in the literature. The effect of using DBSA on the elec-
troconductive properties of the PANI/GO nanocomposites
pressed at different pressures has not been yet reported.
Experimental
Materials
All chemical reagents used in this study were of analytical
laboratory grade, purchased from different sources and
used without any further purification. Graphite, aniline,
DBSA, potassium permanganate (KMnO4), and ammo-
nium peroxydisulfate (APS, (NH4)2S2O8) were procured
from Sigma-Aldrich. Hydrochloric acid (36.46, HCl),
hydrogen peroxide (34.01, H2O2), sulfuric acid (98 %
H2SO4), and acetone were purchased from Dae-Jung
Chemicals, South Korea.
Synthesis
Synthesis of GO
GO was prepared from natural graphite powder by modi-
fying the Hummers and Offeman’s method [21]. In a typ-
ical experiment, 1 g graphite powder was added into
17.5 ml H2SO4 and stirred for 2 h while adding 3 g
KMnO4 gently to maintain the temperature of the solution
at B20 �C under constant stirring. The resulting mixture
was then stirred at 35 �C for 30 min and then at 75 �C for
45 min. 23 ml H2O was added into the solution and heated
at 90 �C for 30 min then 75 ml H2O and 10 ml 30 % H2O2
solution was added to terminate the oxidation. The mixture
was then washed with 5 % HCl aqueous solution repeat-
edly until the pH became neutral. 80 ml water was added
J Mater Sci
123
into the resulting precipitate and sonicated well to obtain
GO. The brown dispersion was centrifuged at 4000 rpm for
2 h to remove any unexfoliated GO.
Synthesis of GO/PANI nanocomposites
For the synthesis of PANI/GO nanocomposites, a solution
containing 2.32 ml of aniline, 12.24 g of DBSA, and
125 ml xylene was prepared in a flask. Another solution of
10 ml DI water, 2.34 g APS, and 1, 2, or 5 wt% of GO was
simultaneously prepared under sonication for 30 min. This
solution was then added into the aniline solution drop-wise
over a 30-min period to avoid overheating. The polymer-
ization reaction was allowed to proceed for 24 h and then
375 ml of acetone was added to stop the reaction with a
subsequent precipitation of the solution to obtain PANI/GO
complex. A dark green powder was recovered by filtration,
and washed three times with 75 ml acetone to remove
impurities such as APS, free DBSA, and unreacted aniline
monomer. Finally, the powder was dried in a vacuum
desiccator at room temperature for 48 h.
Characterization
X-ray diffraction (XRD) measurements were performed
using a Rigaku rotating anode X-ray Diffractometer (D/
MAX-2500/PC, Rigaku, Japan) with a scanning speed of
5�/min from 10� to 60� equipped with a Cu-Ka radiation
source (k = 0.15418 nm) at an accelerating voltage of
50 kV and current of 100 mA. The UV–Vis spectra were
recorded using an Optizen 2120 (Perkin Elmer Lambda
35UV, South Korea) spectrophotometer. Fourier transform
infrared (FTIR) spectroscopic measurements of nanocom-
posite pellets were performed using a Nicolet 6700 with a
diamond probe (Thermo Fisher Scientific, MA) within the
range of 4000 to 500 cm-1.
Morphologies of the samples were studied by High
Resolution transmission electron microscopy (HRTEM,
JEM-2100F, JEOL, Japan) and Scanning electron micros-
copy (SEM, JEOL JSM-6330F, Japan). Thermogravimetric
analysis (TGA, TA Instruments, Q500, USA) of the poly-
mer nanocomposites was performed at a heating rate of
20 �C/min under nitrogen environment. Electrical con-
ductivities of the nanocomposite pellets were measured at
room temperature using a collinear 4 probe apparatus
(CMT-SR2000N, Chang Min Co., Ltd., South Korea) with
typical probe spacing s *1 mm. In this method, current is
supplied via a pair of current leads. The voltage drop across
the impedance is measured by a separate pair of leads.
Thus, the voltage drop in the current-carrying wires is
prevented from being added to the actual value. An average
value was reported from three measurements. The pellets
were prepared by compressing nanocomposites into a press
(Auto M-NE, H 3981, CARVER, USA) for 2 min with a
diameter of 10 mm and thickness of 3–4 mm under pres-
sure of 2, 4, and 6 t.
Results and discussion
Even though the EP of aniline using DBSA or other
emulsifiers has been extensively reported [1, 18, 22–24], in
our present study we attempt to modify the technique by
introducing GO as a dopant to improve the properties of the
resulting nanocomposites. It was previously reported [12,
13, 25, 26] that the synthesis of PANI requires strong acids
such as HCl and HOCl4 since the PANI morphology and
the path of polymerization are greatly influenced by the
acidic conditions [27]. Nevertheless, in situ polymerization
using DBSA as both an emulsifier and protonating agent is
more beneficial in precluding the use of strong acids. Under
this systematic synthetic approach, homogeneous disper-
sion of GO in PANI to form nanocomposites with superior
properties (high crystallinity, high electrical conductivity,
and better thermal stability) can exquisitely be attained.
Figure 1 shows the SEM images of GO, PANI, and GO/
PANI nanocomposites. Figure 1a shows that the GO
exhibited wrinkled and layered stacking with the lateral size
up to several micrometers [28], whereas the rod-like struc-
tures of PANI can be observed in Fig. 1b. Figure 1c–e shows
the images of GO/PANI nanocomposites with 1, 2, and 5
wt% GO, respectively. It can be noticed that the morphology
of PANI/GO nanocomposites is significantly different from
that of PANI and GO. PANI/GO nanocomposites exhibited
multiple shapes, mainly flakes along with some fibrillar
morphology. This change in the morphology of PANI
structure with the addition of GO is consistent with the
findings of Yu et al. [12]. Aniline monomer gets absorbed on
the surface of GO flakes and as the polymerization reactions
proceed on the surface of GO flakes, the resulting nano-
composites display a flaky structure. The GO is well dis-
persed in PANI matrix in the case of nanocomposites. The
morphologies of GO, PANI, and PANI/GO nanocomposites
were further compared with HRTEM analysis.
Figure 2 shows the HRTEM images of GO, PANI, and
PANI/GO nanocomposites. The morphology of pure PANI
synthesized by EP indicates the formation of tube-like
structures (Fig. 2b). However, the images of PANI/GO
with 1, 2, and 5 wt% GO presented in Fig. 2c–e reveal
morphologies different from those of pure PANI. This
might be due to the fact that the polymerization reactions
were carried out in the presence of GO sheets. It is note-
worthy that GO is uniformly distributed in the PANI and
no GO agglomerates can be seen. Uniform dispersion of
GO in PANI matrix helps to obtain improved thermal and
electrical properties for the resulting nanocomposites.
J Mater Sci
123
The XRD patterns of the GO and PANI/GO nanocom-
posites are presented in Fig 3. GO shows a characteristic
peak at 2h = 11�, corresponding to the interlayer spacing
of 0.803 nm between GO sheets. For the PANI/GO nano-
composites, no obvious GO peak can be seen in the results.
In the case of PANI/GO (1 wt%) nanocomposite, the peak
for GO is completely missing which reveals that the layers
of GO are completely exfoliated. This exfoliation of GO
helps to align the PANI chains and enhances the crystal-
linity, which is why PANi/GO exhibits high crystallinity as
compared to the other nanocomposites [13, 29]. In the case
of PANI and PANI/GO nanocomposites, the crystalline
peaks appear at 2h = 17.4�, 18.5�, 23.2�, 25.1�, 26.1�, and
30.3�. Intense peaks at 18.5� and 25.1� corresponding to (0
2 0) and (2 0 0) crystal planes are the characteristic peaks
for PANI [10]. Other sharp peaks are attributed to the
branches of DBSA, which act concurrently as a surfactant
and protonating agent for the resulting PANI [1]. The XRD
results confirmed the formation of nanocomposites, and the
sharp peaks indicate that the resulting PANI and its
nanocomposites had high crystallinity.
Figure 4 shows the FTIR spectra of GO, PANI, and
PANI/GO nanocomposites synthesized through this pro-
cess. The GO showed absorption bands at 1740, 1270,
1082, and 3230 cm-1 indicating the presence of carboxyl
(–COOH), epoxy, carbonyl ([C=O), and hydroxyl (–OH)
groups, respectively. The peak at 1620 cm-1 is associated
with the vibration of the absorbed water molecules and
may also be due to the skeletal vibration of the unoxidized
graphitic domain [13, 30]. For PANI, the absorption band
at 1580 cm-1 is characteristic of the imine ([C=N–) group
stretching in the quinoid units [29]. This peak is shifted to
Fig. 1 SEM images of a GO; b PANI and GO/PANI composites with GO concentration of c 1 wt%, d 2 wt%, and e 5 wt%
Fig. 2 TEM images of a GO; b PANI and GO/PANI composites with GO concentration of c 1 wt%, d 2 wt%, and e 5 wt%
J Mater Sci
123
1395 cm-1 in PANI/GO nanocomposites indicating that
the carboxyl group of GO was linked to the nitrogen of the
PANI backbone during polymerization to form cross-
linked nanocomposites [13].
The UV–Vis spectra of GO, PANI, and PANI/GO
nanocomposites are displayed in Fig. 5. The absorption
peak at 226 nm in the GO sample is attributable to the
p–p* electronic transition of the aromatic carbon–carbon
(–C–C–) bonds[30]. PANI and PANI/GO nanocomposites
revealed four different characteristic absorption bands at
254, 361, 460, and 700–800 nm. The absorption bands at
460 and 700–800 nm in the pure PANI spectrum are
sharper. The absorption band at 254 nm corresponds to the
excitation of p–p* transition in the benzenoid rings of
DBSA and the excitation of benzenoid segments in the
PANI [1]. The band at 361 nm represents the p–p* electron
transition in benzenoid rings [28]. The bands at 460 and
700–800 nm belong to the acid-doped state and the polaron
formation in polyaniline, respectively. The band at 460 nm
verifies the increase in the doping level of PANI [31].
TGA and derivative TGA (DTG) curves of GO, PANI,
and PANI/GO nanocomposites are shown in Figs. 6 and 7,
respectively. The initial weight loss of the GO, PANI, and
PANI/GO nanocomposites at around 130 �C is due to
evaporation of water and moisture present in the samples.
The weight loss for GO between 150 and 350 �C of about
30 % is attributed to the removal of the oxygen-containing
groups (hydroxyl (–OH) and carboxyl (–COOH)) [10].
Notable weight loss in the PANI sample between 150 and
600 �C is assigned to the thermal decomposition of bound
DBSA and PANI matrix [1]. The derivative thermogravi-
metric peak temperature (Tp) corresponding to the maxi-
mum weight loss increases with increasing GO loadings.
The Tp value for PANI is 333 �C, which is relatively
shifted to 346, 344, and 340 �C for samples with 1, 2, and 5
wt% GO content, respectively. The PANI with 1 wt% GO
nanocomposite showed the highest thermal degradation
temperature, which might be due to the homogeneous
dispersion of GO throughout the PANI matrix as well as
strong interfacial interactions between GO and the PANI
matrix through p–p* and hydrogen-bonding interactions.
The most probable hydrogen-bonding interaction is formed
between the amine group (–NH–) of PANI as a proton
donor and surface hydroxyl groups (–OH) of GO as proton
acceptor. However, the nanocomposites with 2 and 5 wt%
GO show a degradation temperature slightly lower than
that of the sample with 1 wt% GO loading, which could be
due to the reduced interaction between the PANI and GO at
higher GO contents [10].
Figure 8 shows the electrical conductivities of PANI and
PANI/GO nanocomposite pellets with different GO con-
tents. It can clearly be seen that the electrical conductivity of
the PANI/GO nanocomposite pellets increased significantly
with increasing GO contents and applied pressure. Even
though the pellets pressed by 2 t show a slight increase, a
remarkable increase can be observed in the samples pressed
by 4 and 6 t. These findings are consistent with those reported
by Zhang [19], signifying that increasing the pressing pres-
sure eliminates voids or entrapped air inside the pellets, and
also the fillers inside the polymer matrix come close to each
other to form conductive paths, which reduces the resistance
of the PANI/GO nanocomposites. This phenomenon is dis-
cussed in detail by Hussain et al. [32]. At 2 t of pressing
pressure, the conductivity of the nanocomposites does not
increase sharply because the considerable removal of voids
from the pellets usually takes place at higher compression
pressures [33]. Table 1 summarizes the electrical conduc-
tivities of the PANI nanocomposites reported by different
researchers.
Various studies [1, 19, 34] have substantially reported
PANI blended with different materials to increase its
electrical conductivity. Han et al. [1] used reverse micelle
polymerization to synthesize DBSA-doped PANI nano-
particles with different doping ratios, and a maximum
conductivity of 74 S/m was reported. Meanwhile, Zhang
10 20 30 40 50 60
(e)
(d)
(c)
(b)
Inte
nsit
y (a
.u.)
2Theta degree
(a)
Fig. 3 XRD Patterns of (a) GO; (b) PANI and GO/PANI composites
with GO concentration of (c) 1 wt%, (d) 2 wt%, and (e) 5 wt%
4000 3000 2000 1000
80
100
120
140
160
180 (e)
(d)
(c)
Tra
nsm
itta
nce
(a.u
)
Wavenumber (cm-1)
(a)
(b)
Fig. 4 FTIR spectra of (a) GO; (b) PANI and GO/PANI composites
with GO concentration of (c) 1 wt%, (d) 2 wt%, and (e) 5 wt%
J Mater Sci
123
[19] found that the electrical conductivity of PANI can be
increased to 750 S/m in the presence of p-toluene sulfonic
acid (TSA) as a dopant. However, the electrical properties
of PANI nanocomposites depend not only upon the dopants
but also on the structure of the nanocomposite (powder,
fiber, film etc.), synthesis method, particle size, and
architecture of the constituents comprising the nanocom-
posites [11, 25, 35]. Lu et al. [25] designed and synthesized
a hierarchical film with coaxial PANI/CNT sandwiched
between graphene sheets. The electrical conductivities of
these samples were 70, 680, and 150 S/m for PANI, PANI/
CNT, and PANI/GN, respectively. Particularly, the elec-
trical conductivities of PANI/GO and PANI/GO/CNT were
10 and 410 S/m, respectively. It is obvious that the con-
ductivity of PANI/GO was lower than that of pure PANI
implying that the morphology of the nanocomposites has a
profound effect on the electrical conductivity of the
materials. In the present study, the highest notable elec-
trical conductivity (474 S/m) was achieved in the sample
with 5 wt% GO pressed by 6 t at room temperature. This
appreciable improvement is attributable to the uniform
distribution of GO in PANI and the high crystalline
structure of as-prepared PANI/GO nanocomposites as was
confirmed by the XRD results. Moreover, Zhao et al. [13]
determined the electrical conductivities of PANI/GO
nanocomposites pressed by 10 t at elevated temperatures
(50, 70, and 90 �C), and the sample with 5 wt% GO con-
tent displayed 400 S/m. It is noteworthy that PANI/GO
nanocomposites of the present study demonstrated higher
conductivity (at room temperature and low pressing pres-
sure) than has previously been reported.
Abs
orba
nce
(a.u
)
Wavelength (nm)
GO
200 300 400 500 600 700 800 200 300 400 500 600 700 800
(d)
(c)
(b)
Abo
srba
nce
(a.u
)
Wavelength (nm)
(a)
Fig. 5 UV–Vis absorption spectra of GO, (a) PANI and GO/PANI composites with GO concentration of (b) 1 wt%, (c) 2 wt%, and (d) 5 wt%
0 200 400 600 800 1000
20
40
60
80
100
(e)
(d)
Wei
ght
(%)
Temperature (oC)
(a)
(c)
(b)
Fig. 6 TGA analysis of (a) GO; (b) PANI and GO/PANI composites
with GO concentration of (c) 1 wt%, (d) 2 wt%, and (e) 5 wt%
0 200 400 600 800 1000
0.0
0.2
0.4
0.6
0.8
1.0
1.2
Der
iv. W
eigh
t (%
/o C)
Temperature (oC)
(a)
(b)
(e)(c)
(d)
Fig. 7 DTG analyses of (a) GO; (b) PANI and GO/PANI nanocom-
posites with GO concentration of (c) 1 wt%, (d) 2 wt%, and
(e) 5 wt%
0 2 4 6
100
200
300
400
500
6 ton
4 ton
Con
duct
ivit
y (S
/m)
GO(wt%)
2 ton
Fig. 8 Electrical conductivity of PANI and GO/PANI composites at
different pressures
J Mater Sci
123
The main objective of the present study was to establish
a simple method to disperse GO into PANI to harness the
electrical conductivities of the resulting composites. The
SEM and HRTEM micrographs revealed that GO was well
dispersed indicating that during in situ polymerization of
PANI, dopants such as GO can be introduced to form
composites with improved properties. Moreover, XRD,
UV, and FTIR analysis demonstrated the formation of
composites with high crystallinity and excellent chemical
interaction of PANI and GO, which are substantial attri-
butes for enhancing the electrical properties of materials
[19, 20]. The evaluation of the electrical properties indi-
cated that the conductivities of the composites were criti-
cally dependent on the amount of the dopant, synthesis
method, and pressing pressure during pellet preparation. It
is noteworthy that PANI/GO nanocomposites reported in
the present study exhibited electrical conductivity values
which are superior to those reported in the literature [12,
13, 35]. Therefore, the formation of composites with
improved electrical conductivities by the synthetic
approach introduced by this work is interesting and
recommendable.
Conclusions
We reported the synthesis and characterization of PANI/GO
nanocomposites with GO content ranging from 1 to 5 wt%.
Modified in situ EP route was employed to form PANI/GO
nanocomposites in the absence of strong acids. The structural
and electrical properties were studied under different char-
acterization techniques. TEM results showed the uniform
distribution of PANI on the GO surface, whereas SEM
results showed that GO was well covered with a PANI
matrix. XRD results of the nanocomposites indicated that
both polymer and nanocomposites had high crystallinity due
to doping with DBSA during the polymerization process.
UV–Vis and FTIR results confirmed the existence of inter-
actions between GO and PANI to form nanocomposites.
TGA results clearly indicated that the GO contents were
essential for improving the thermal stability and electrical
properties of PANI. Maximum conductivity (474 S/m) was
attained in samples with 5 wt% GO content and a pressing
pressure of 6 tons. This work provides an effective, easy,
cheap, and reproducible method to synthesize PANI/GO
nanocomposites with desirable properties suitable for vari-
ous semiconductor applications.
Acknowledgements This work was supported by the Korea Insti-
tute of Energy Technology Evaluation and Planning (KETEP) from
the Ministry of Trade, Industry and Energy of the Republic of Korea
through the Human Resources Development Program (Grant No.
20124030200130).
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Table 1 Comparison of the electrical conductivities of PANI-based composites obtained at different conditions
Report Sample
name
Pressing
pressure (t)
Measurement
temperature (�C)
GO
(wt%)
Conductivity
(S/m)
Zhao et al. [13] PANI/GO 10 90 5 400
Zhao et al. [13] PANI/GO 10 90 40 751
Yu et al. [12] PANI/G – 25 50 420
Lu et al. [25] PANI/GO – 25 – 100
Zhang et al. [19] PANI/TSA 0.56 25 – 750
Han et al. [1] PANI/DBSA – 25 – 74
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