Hierarchical composites of conductivity controllable polyaniline layers on the exfoliated graphite for dielectric application

Yu, Li; Zhang, Yihe; Tong, Wangshu; Shang, Jiwu; Lv, Fengzhu; Chu, Paul K.; Guo, Wenmin

doi:10.1016/j.compositesa.2012.06.001

Cited by 39 publications

(23 citation statements)

References 33 publications

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“…The incorporation of EG in a polyimide film is associated with a percolation threshold of 3.1 vol% [78]. The addition of a polyaniline fibers to the surface of EG prior to incorporation in poly(vinylidene fluoride) gives a polymermatrix composite with relative dielectric constant 17 and dielectric loss 0.06 at 1 kHz [79]. The low loss is attributed to the non-conductive fibers causing the EG units not to touch one another in the composite.…”

Section: Exfoliated Graphite Compositesmentioning

confidence: 98%

A review of exfoliated graphite

2015

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Exfoliated graphite (EG) refers to graphite that has a degree of separation of a substantial portion of the carbon layers in the graphite. Graphite nanoplatelet (GNP) is commonly prepared by mechanical agitation of EG. The EG exhibits clinginess, due to its cellular structure, but GNP does not. The clinginess allows the formation of EG compacts and flexible graphite sheet without a binder. The exfoliation typically involves intercalation, followed by heating. Upon heating, the intercalate vaporizes and/or decomposes into smaller molecules, thus causing expansion and cell formation. The sliding of the carbon layers relative to one another enables the cell wall to stretch. The exfoliation process is accompanied by intercalate desorption, so that only a small portion of the intercalate remains after exfoliation. The most widely used intercalate is sulfuric acid. The higher concentration of residue in unwashed EG causes the relative dielectric constant (50 Hz) of the EG to be 360 (higher than 120 for KOH-activated GNP), compared to the value of 38 for the water-washed case. An EG compact is obtained by the compression of EG at a pressure lower than that used for the fabrication of flexible graphite. Compared to flexible graphite, EG compacts are mechanically weak, but they exhibit viscous character, outof-plane electrical/thermal conductivity and liquid permeability. The viscous character (flexural loss tangent up to 35 for the solid part of the compact) stems from the sliding of the carbon layers relative to one another, with the ease of the sliding enhanced by the exfoliation process.

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Section: Exfoliated Graphite Compositesmentioning

confidence: 98%

A review of exfoliated graphite

2015

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“…The morphologies of PANI and PPy nanocomposites with GN and GO are different from those of PANI and PPy. This is due to the presence of GN and GO during the polymerization of the polymers, which results in the sheet‐like structure of the final nanocomposites due to the fact that GN and GO serve as templates during the formation of nanocomposites .…”

Section: Resultsmentioning

confidence: 99%

Study of the electroconductive properties of conductive polymers‐graphene/graphene oxide nanocomposites synthesized via in situ emulsion polymerization

et al. 2016

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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 four‐probe 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. POLYM. COMPOS., 39:2142–2150, 2018. © 2016 Society of Plastics Engineers

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“…Interesting dielectric and/or conductivity studies on PANI/PVDF based materials have been reported . The first high dielectric all‐polymer material using PANI as conducting polymer particulates in the PVDF‐based terpolymer poly(vinylidene fluoride‐ co ‐trifluoroethylene‐ co ‐chloro trifluoro ethylene) [P(VDF‐TrFE‐CTFE)] has been reported more than a decade back .…”

Section: Introductionmentioning

confidence: 99%

Dielectric and conducting behavior of pyrene functionalized PANI/P(VDF‐co‐HFP) blend

Singh

Ramani

Singh

et al. 2016

J of Applied Polymer Sci

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Herein, we present the dielectric and electrical conductivity properties of the partially miscible polymer blend prepared using pyrene functionalized polyaniline (pf-PANI) and poly(vinylidene fluoride-co-hexafluoro propylene) (PVDF-co-HFP). The blend mostly retains the fluorescent nature of pf-PANI as well as can be moldable and possesses good damping property. The dielectric properties have been investigated as a function of temperature at three different frequencies and the plausible origin of polarization responsible for dielectric behavior in this blend has been identified. The experimental results of dielectric measurements are compared with theoretical models and discussed. The surface morphology of the samples has been examined with a scanning electron microscope. The electrical conductivity has also been studied as a function of temperature and explained in terms of hopping of charge carriers/interconnected networks. The combined dielectric and conductivity results together with scanning electron microscope micrographs, reveal that there is hindrance to achieve percolation threshold even after pf-PANI addition of 57 vol % and subsequent thermal treatment.

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Hierarchical composites of conductivity controllable polyaniline layers on the exfoliated graphite for dielectric application

Cited by 39 publications

References 33 publications

A review of exfoliated graphite

A review of exfoliated graphite

Study of the electroconductive properties of conductive polymers‐graphene/graphene oxide nanocomposites synthesized via in situ emulsion polymerization

Dielectric and conducting behavior of pyrene functionalized PANI/P(VDF‐co‐HFP) blend

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