Reduced percolation thresholds of immiscible conductive blends

Foulger, Stephen H.

doi:10.1002/(sici)1099-0488(19990801)37:15<1899::aid-polb14>3.0.co;2-0

Cited by 125 publications

(77 citation statements)

References 24 publications

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“…[44][45][46] In our case, the percolation threshold of CB-filled polymers was determined at the resistivity changed from insulation behavior (>10 11 ΩÁcm) to conduction behavior (<10 4 ΩÁcm). [44][45][46] In our case, the percolation threshold of CB-filled polymers was determined at the resistivity changed from insulation behavior (>10 11 ΩÁcm) to conduction behavior (<10 4 ΩÁcm).…”

Section: Resultsmentioning

confidence: 99%

Improvement of polyimide/polysulfone composites filled with conductive carbon black as positive temperature coefficient materials

Tiptipakorn

Kuengputpong

Okhawilai

et al. 2019

J of Applied Polymer Sci

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In this study, polyimide (PI)/polysulfone (PSF) blends filled with carbon black (CB) were developed for the use as positive temperature coefficient (PTC) materials in order to achieve the volume resistivity as lower than 10 4 Ω.cm at room temperature. The weight ratios of PI/PSF were various from 100/0 to 10/90 with CB varied from 0 to 20 wt%. The use of conductive filler was reduced when PSF was blended with PI; the blends clearly possessed a percolation threshold decreased by 90%. The electrical conductivity of the CB-filled blends was higher than those of CB-filled pure PI. The transition temperature for PTC material was reported in the range of 180 to 210 C. The preferential location of CB filler in PI domains could be observed using the optical microscope. In addition, the composites met the standards for the obtained mechanical and thermal properties, exhibiting the potential use as PTC materials.

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Section: Resultsmentioning

confidence: 99%

Improvement of polyimide/polysulfone composites filled with conductive carbon black as positive temperature coefficient materials

Tiptipakorn

Kuengputpong

Okhawilai

et al. 2019

J of Applied Polymer Sci

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“…It is well‐known that the charge carriers in the different phases of the composite would be trapped at the interfaces within the dielectrics . These charges are unable to discharge freely and give rise to an overall field distortion, leading to an increase in capacitance, which is called interfacial polarization (MWS polarization) phenomenon occurred at the interface of dissimilar materials . In PZN−PZT/16.6 vol% Ag composites, the dielectric field developed around the core−shell structures, which can enhance the interfacial polarization, leading to a much larger increase in the effective dielectric constant.…”

Section: Resultsmentioning

confidence: 99%

Novel Core–Shell Nanostructure in Percolative PZN−PZT/Ag Ferroelectric Composites

2014

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Novel percolative PZN−PZT/Ag ferroelectric composites with intragranular structure were prepared with micro‐PZN−PZT and nano‐Ag particles. The typical core–shell nanostructures were systematically investigated by TEM, in which, the nanoscale shells act as interlayers between the Ag cores and the ceramic matrix. Excellent dielectric properties, such as high dielectric constant (εr ~16600) and low dielectric loss (< 0.056) were reported. The high dielectric constant originates from the coeffect of “microcapacitors” and Maxwell–Wager–Sillars (MWS) polarization. Especially, the core−shell structure may reinforce the MWS effect. Meanwhile, the insulating interlayers reduce the tunnel current between neighboring Ag cores by causing potential barriers, endowing the nanocomposites with low dielectric loss. This approach can be used to realize a novel material with high dielectric constant over a wide frequency and temperature range.

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“…This volume exclusion effect is similar to that which occurred in the various studies involving immiscible polymer blends with fillers. [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] The fillers become excluded from one polymer phase, thereby forcing them together and producing samples with lower percolation threshold concentrations. As we added more beads, the viscosity of the sample rose at a rapid rate.…”

Section: Resultsmentioning

confidence: 99%

Polymer beads in microtubule-filled composites: Effects on length distributions and permittivities

Chiou

Lankford

Schoen

2004

Journal of Applied Physics

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The effects of adding poly(methylmethacrylate) beads to tubule-filled composites were examined in terms of changes in tubule distribution and dielectric properties of the composites. The beads had an average diameter of 51±29 μm, whereas the copper-coated tubules, which were shaped like hollow cylinders and derived from a phospholipid template, had an average length of 30±22 μm and an average diameter of 1 μm. Incorporating a small amount of beads increased the permittivity value of the composite, but adding more beads resulted in a dramatic decrease in the permittivity value. In fact, a permittivity maximum appeared at around 5 vol % beads for various tubule loadings. The results could be explained in terms of volume exclusion and decreased tubule length effects. At low bead loadings, the volume exclusion effect dominated as the tubules were pushed closer together, resulting in a higher permittivity value. At higher bead loadings, the tubules were broken into shorter pieces and this became the dominant effect. Consequently, the shorter tubules formed fewer conducting pathways and the permittivity declined in value. In addition, the De Loor model for composites containing a dielectric matrix and conductors as fillers correctly predicted a permittivity maximum and provided the best fit to the permittivity data.

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Reduced percolation thresholds of immiscible conductive blends

Cited by 125 publications

References 24 publications

Improvement of polyimide/polysulfone composites filled with conductive carbon black as positive temperature coefficient materials

Improvement of polyimide/polysulfone composites filled with conductive carbon black as positive temperature coefficient materials

Novel Core–Shell Nanostructure in Percolative PZN−PZT/Ag Ferroelectric Composites

Polymer beads in microtubule-filled composites: Effects on length distributions and permittivities

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