Nanocomposites and nanomaterialsс

Low temperature charge transport in the hybrid PVDF-PANI-MWCNT nanocomposite 
R.M. Rudenko1, O.O. Voitsihovska1, V.M. Poroshin1, M.V. Petrychuk2, S.P. Pavlyuk2, N.A. Ogurtsov3, Yu.V. Noskov3,  D.O. Sydorov3, A.A. Pud3
1 Institute of Physics, National Academy of Sciences of Ukraine, 46 avenu Nauky, 03680, Kyiv, Ukraine (e-mail: rudenko.romann@gmail.com)
2 Taras Shevchenko National University of Kyiv, 4g avenu Academician Glushkov, 01133, Kyiv, Ukraine
3 Institute of Bioorganic Chemistry and Petrochemistry, National Academy of Sciences of Ukraine, 50 Kharkivske Shose, 02160, Kyiv, Ukraine
In this paper, we present results of an investigation of the low temperature charge transport of hybrid nanocomposite film materials based on ferroelectric polymer polyvinylidene fluoride (PVDF), conducting polymer polyaniline doped by dodecylbenzenesulfonic acid (PANI) and different contents (0-15%) of multi-wall carbon nanotubes (PVDF-PANI-MWCNT). Composite materials based on conductive polymers and thermoplastics have a good electrical conductivity and mechanical properties, which make them promising materials for a wide field of applications. The incorporation of carbon nanotubes into polymeric composite materials improves their conductivity and mechanical properties [1]. However, charge transfer properties of such hybrid composite materials are not enough studied and understood yet .
In order to better understand the mechanisms of conductivity in the hybrid nanocomposite films PVDF-PANI-MWCNT, we investigated temperature dependences of resistivity over a wide temperature range of 4.2–300 K. Dependence analysis indicated that at low temperatures in the low-bias (Ohmic) regime the charge carrier transport proceeds due to the variable range hopping (VRH) mechanism and the resistance changes follow R~exp[(T0/T)]1/2. However, at the temperature of 4.2 K and sufficiently high electric fields (E up to 105–106 V/m), i.e. the high bias non-Ohmic regime, the hopping is field driven and the data follow R~exp[(E0/E)]1/2. Thus, in the studied materials Efros-Shklovskii VRH conduction mechanism is realized which takes into account the Coulomb interaction of charge carriers. This allowed us to determine the localization length of charge carriers and the dielectric constant for the studied hybrid nanocomposite PVDF-PANI-MWCNT for different contents of carbon nanotubes.

1.	Martins J.N., Kersch M., Altstädt V., Oliveira R.V.B. Poly(vinylidenefluoride)/polyaniline/carbon nanotubes nanocomposites: Influence of preparation method and oscillatory shear on morphology and electrical conductivity // Polymer Testing.-2013.-32.-P. 1511-1521.