Nanocomposites and nanomaterials

Electrical properties of epoxy composites with carbon nanotubes, mixed with TiO2 or Fe particles
O.V. Lozitsky1, L.L. Vovchenko1, L.Y. Matzui1, Y.S. Milovanov2
1 Department of Physics, Taras Shevchenko National University of Kyiv, Volodymyrska str., 64/13, Kyiv, 01601, Ukraine. 
E-mail: Olozitsky@gmail.com
2 Institute of High Technologies, Taras Shevchenko National University of Kyiv, Volodymyrska str., 64/13, Kyiv, 01601, Ukraine.

Using of polymer composite materials (CMs) with carbon nanotubes (CNT), Fe and TiO2 particles has proven useful for affecting the microwave radiation [1]. Using epoxy resin L285 as the polymer matrix, this work presents the data on low-frequency properties of CNT/TiO2/L285 and CNT/Fe/L285 CMs, including impedance spectroscopy and AC conductivity (figure 1) in frequency range 10 Hz – 2 MHz. The research also involved determining characteristic capacitances and resistances of a CM through equivalent circuit model [2].
The conductivity measurements show the increase with frequency for most CMs and each CM has a frequency, below which the conductivity stays constant. Overall, the research shows that CNT/Fe/L285 CM produces higher conductivities, compared to CNT/TiO2/L285 CM or CNT/L285 with the same CNT content, thanks to conductive nature of Fe particles.
Figure 1. AC conductivity of CNT/Fe/L285 CMs.
Also, CM 5 wt. % CNT/Fe/L285 exhibits a decrease of conductivity with higher frequency, indicating a transition to metallic charge transport. Good matching of modeled and measured impedance diagrams was achieved, allowing it to determine the equivalent electrical parameters of the CMs to simplify material characterization and potentially use the materials modeling for practical applications. 

1.	Green M., Chen X. (2019). Journal of Materiomics, 5(4), 503
2.	Compf B, Dressel M, Berrier A (2018). Appl. Phys. Lett. 113: 243104