Study of the Electroconductive Properties of Conductive Polymers-Graphene/Graphene Oxide Nanocomposites Synthesized via in Situ Emulsion Polymerization
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Date
2018
Authors
Journal Title
Journal ISSN
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Publisher
Wiley
Abstract
The present study introduces a modified approach to
synthesize polyaniline (PANI) and polypyrrole (PPy)
doped with graphene oxide (GO) or graphene (GN)
through an in situ emulsion polymerization (EP) technique. Dodecyl benzene sulfonic acid (DBSA) was used
as a surfactant and doping agent as well during the
polymerization reaction. The morphology and microstructure of the synthesized polymers and their nanocomposites were studied by scanning electron
microscopy, transmission electron microscopy, Fourier
transform infrared spectroscopy, X-ray photoelectron
spectroscopy, and thermogravimetric analysis. All of
these characterization techniques confirmed the superior morphology and thermal properties of the nanocomposites. The electroconductive properties of the
synthesized polymers and their nanocomposite pellets
containing 5 wt% of either GN or GO pressed at pressures of 2, 4, and 6 tons were investigated with a fourprobe analyzer. Nanocomposites showed very high
electrical conductivity compared to individual PANI and
PPy samples pressed at the same pressures. The addition of GO and GN not only improved the thermal stability but also significantly enhanced the electrical
conductivity of the nanocomposites. Thus, the present
work signifies the importance of the direct loading of
GO and GN into conductive polymers during the EP
process using DBSA as a surfactant to achieve nanocomposites with promising properties for various
semiconductive applications.
Description
In this study, we reported the synthesis and characterizationof two different conductive polymers (PANI and
PPy) and their nanocomposites with GO and GN (5
wt%). These polymers were modified via in situ EP using
DBSA as both a surfactant and a doping agent. AT-FTIR
results showed the successful interaction between the
polymer chains and GO/GN. The XRD peaks for PANI
and its nanocomposites were very sharp, indicating that
they were crystalline in nature, whereas the broadened
PPy peak in the case of PPy nanocomposites indicated
the interaction between PPy and the GO/GN layers.
FESEM results indicated that the resulting nanocomposites of both conductive polymers had sheet-like morphologies due to the presence of GO and GN during
polymerization. Additionally, TEM results confirmed that
PANI and PPy were well-distributed on the surface of
GO and GN. TGA results clearly indicated that the thermal properties were enhanced on the addition of GO and
GN in the conductive polymer matrices. All of the nanocomposites demonstrated higher values of electrical conductivity at room temperature with 5 wt% of GO and GN
as doping agents. PPy nanocomposites with GO and GN
showed the highest electrical conductivities (475.67 and
643.5 S/m, respectively) due to the improved interaction
of PPy chains with GO and GN, as compared to PANI.
This work provides an effective and reproducible method
to fabricate conductive polymers (and their nanocomposites) that possess superior and desirable structural and
electrical properties for various semiconductor devices.
Keywords
graphene; graphene oxide; conductive polymers