Development of Kovacs model for electrical conductivity of carbon nanofiber–polymer systems

Abstract

This study develops a model for electrical conductivity of polymer carbon nanofiber (CNF) nanocomposites (PCNFs), which includes two steps. In the first step, Kovacs model is developed to consider the CNF, interphase and tunneling regions as dissimilar zones in the system. In the second step, simple equations are expressed to estimate the resistances of interphase and tunnels, the volume fraction of CNF and percolation onset. Although some earlier models were proposed to predict the electrical conductivity of PCNFs, developing of Kovacs model causes a better understanding of the effects of main factors on the nanocomposite conductivity. The developed model is supported by logical influences of all factors on the conductivity and by experimented conductivity of several samples. The calculations show good accordance to the experimented data and all factors rationally manage the conductivity of PCNFs. The highest conductivity of PCNF is gained as 0.019 S/m at the lowest ranges of polymer tunnel resistivity (ρ = 500 Ω m) and tunneling distance (d = 2 nm), whereas the highest levels of these factors (ρ > 3000 Ω m and d > 6 nm) cannot cause a conductive sample. Also, high CNF volume fraction, poor waviness, long and thin CNF, low “k”, thick interphase, high CNF conduction, high percentage of percolated CNFs, low percolation onset and high interphase conductivity cause an outstanding conductivity in PCNF.

State-of-the-art of electrospun nanocomposite nanofibers and membranes with carbon nanoparticles—Prevailing progressions

“…Using electrospinning, carbon nanotube has been filled in nanofibers of polymers [59] . The polyamide and poly(ethylene glycol) thermoplastic matrices have been reinforced with carbon nanotube to form electrospun nanofibers [61] . In addition, conducting polymer like polyaniline has been filled with carbon nanotube to synthesize the nanofibers [62] .…”

Electrospinning Processing of Polymer/Nanocarbon Nanocomposite Nanofibers—Design, Features, and Technical Compliances

“…A carbon nanotube forms electrospun nanofibers with various polymers such as poly(ethylene glycol) and polyamide [94,95]. Electrospun poly(ethylene glycol)/carbon nanotube nanofibers have been reported with a fine morphology and high-power density of 156 mWcm −2 [96,97]. Kaynan et al [98] designed pol(vinyl butyral)and carbon nanotube-derived nanocomposite nanofibers.…”

“…high-power density of 156 mWcm −2 [96,97]. Kaynan et al [98] designed pol(vinyl butyral)and carbon nanotube-derived nanocomposite nanofibers.…”

Percolation onset and conductivity of nanocomposites assuming an incomplete dispersion of graphene nanosheets in a polymer matrix

“…Therefore, an opposite link between conductivity and tunneling length based on the innovative model is true, as suggested by previous studies. 51,53,54…”