Preparation, Characterization and Electromagnetic Interference Shielding Effectiveness Of Ppy-Pva and Ppy-Cmc Conducting Polymer Composite Films
Polypyrrole-poly(viny1 alcohol) (PPy-PVA) and polypyrrole-carboxymethyl cellulose (PPy-CMC) conducting polymer composite films were electrochemically prepared on Indium Tin Oxide (ITO) glass electrode from an aqueous solution containing pyrrole monomer, p-toluene sulfonate dopant and poly(viny1...
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| Format: | Thesis |
| Language: | English English |
| Published: |
2006
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| Subjects: | |
| Online Access: | http://psasir.upm.edu.my/id/eprint/6282/1/FS_2006_10.pdf |
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| Summary: | Polypyrrole-poly(viny1 alcohol) (PPy-PVA) and polypyrrole-carboxymethyl
cellulose (PPy-CMC) conducting polymer composite films were electrochemically
prepared on Indium Tin Oxide (ITO) glass electrode from an aqueous solution
containing pyrrole monomer, p-toluene sulfonate dopant and poly(viny1
alcohol)/carboxymethyl cellulose insulating polymer. The PPy-PVA and PPy-
CMC composite films prepared from different process conditions were
characterized by Fourier Transform infrared (FT-IR) spectroscopy, X-ray
diffraction (XRD) analysis, optical microscopy, dynamic mechanical analysis
(DMA), and conductivity measurement. The highest conductivity of 64 Slcm
measured at room temperature was shown by PPy-PVA composite film prepared
fiom 0.2 M pyrrole, 0.1 M p-toluene sulfonate and 12 x lo4 M PVA at 1.2 volt (vsSCE) among all the PPY-PVA composite films produced. The PPy-CMC
composite film prepared from 0.3 M pyrrole, 0.1 M p-toluene sulfonate and 0.03 M
CMC at 1.2 volt (vs SCE) showed the highest conductivity of 38 Slcm among all
the PPy-CMC composite films produced. The FT-IR study of PPy-PVA and PPy-
CMC composite films shows the evidence of the incorporation of PVA and CMC
in PPy structure forming PPy-PVA and PPy-CMC composite films, respectively.
The conductivity data of PPy-PVA shows that with the increase in PVA
concentration in the pyrrole solution, the conductivity of the prepared PPy-PVA
film is increasing up to certain level due to the increase in conjugation length and
later it is decreasing with further increase in PVA concentration, which is again
linked with the conjugation length decrease. This is supported by the FT-IR band
intensity of Ic=c/Ic-N. The FT-IR study of PPy-CMC composite films shows that
with the increase in CMC concentration from 0.005 M to 0.01 M, the conductivity
first decreased and later with further increase in CMC concentration the
conductivity showed an increasing trend and finally at 0.04 M CMC, the
conductivity dropped.
The DMA results of PPy-PVA and PPy-CMC composite films show the enhanced
mechanical properties of both the composite films over PPy films without PVA or
CMC. The storage moduli of both the composite films were found much higher
than the PPy film prepared without PVA or CMC indicating that PPy-PVA and
PPy-CMC composite films are much stiffer than PPy films. The gradual decrease
of storage moduli of both the composite films with the increase in temperature ranging from 25 "C to 250 "C suggests that the composite films have got flexibility
in their chains and thus the chains are soft. On the other hand, the storage modulus
of PPy film only without PVA or CMC shows no decreasing tendency with the
increase in temperature ranging from 25 "C to 250 "C indicating that the PPy film is
very hard and have got no flexibility in its backbone chain.
The XRD results of both PPy-CMC and PPy-PVA composite films show that the
films are amorphous and have got very little order. The optical micrographs of
PPy-CMC and PPy-PVA show the globular surface morphology. The changes in
globular surface morphology with the change in process condition of the film
preparation indicates that the process parameters used to prepare the composite
films have got a good influence over the surface morphology. The intense
polymerization reaction has been evidenced from the surface morphology of the
films.
The results of electromagnetic interference (EMI) shielding effectiveness in the
microwave range of 8-12 GHz show that the highest shielding effectiveness of
45.67 dB measured in the microwave range of 8-12 GHz corresponds to the total
attenuation of 99.4 % of microwave energy has been exhibited by the Pe-PVA
composite film prepared from 0.2 M pyrrole, 0.1 M p-toluene sulfonate and 12 x
10" M PVA at 1.2 volt (vs SCE) among all the PPy-PVA composite films
prepared. The highest shielding effectiveness of 35.7 dB measured in the
microwave range corresponds to the total attenuation of 98.32 % of microwave
energy has been exhibited by the PPy-CMC composite film prepared fiom 0.3 M pyrrole, 0.1 M p-toluene sulfonate and 0.03 M CMC at 1.2 volt (vs SCE) among all
the PPy-CMC composite films prepared. Thus, the promise of finding any
electromagnetic interference (EMI) shielding applications in the microwave
frequency range lies in PPy-PVA and PPy-CMC conducting polymer composite
films. |
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