Nanocomposites and nanomaterials

Computer and experimental study of field-induced conductivity modulation in liquid crystal – carbon nanotubes system
Yu.I. Olenych1, I.B. Olenych1, Yu.Yu. Horbenko1, O.I. Aksimentyeva1, I.D. Karbovnyk1, B.R. Tsizh2,3
1 Ivan Franko National University of Lviv, 50 Dragomanov Str., Lviv-79005, Ukraine. E-mail: iolenych@gmail.com
2 Stepan Gzytsky Lviv National University of Veterinary Medicine and Biotechnologies, 50 Pekarska str., Lviv-79010, Ukraine
3 Kazimierz Wielki University, 30 Chodkiewicza str., 85-064, Bydgoszcz, Poland

The promising direction for nanotechnology development is the synthesis of nanocomposite materials possessing new functional properties, in particular, systems based on carbon nanotubes (CNTs) incorporated in dielectric matrices. An important condition for the electrical conductivity of such nanosystems is the formation of percolation clusters of CNTs. The threshold value of percolation is usually related to the size of filler particles i.e. the length and radii of the nanotubes as well as their shape, predominant orientation, and dispersion quality [1]. Therefore, the use of liquid crystals (LC) as a host medium of the composite is promising in this field. Structural ordering of LC by the application of electrical or magnetic field makes it possible to manipulate CNTs and control their orientation and hence the electrical properties of the entire system. 
In this work, LC–CNTs systems with different content of nanotubes were created and their electrical properties were studied. We have found that obtained nanosystems show a decrease in internal resistance by four orders of magnitude with increasing the mass concentration of the CNTs from 1 to 8%. In addition, the electrical conductivity of the LC–CNTs systems depends on the applied electric field. Based on computer simulations of percolation processes in the CNTs system, it is shown that changes in the conductivity of obtained nanosystem under the influence of the external electric field are likely associated with the increase in the percolation probability when limiting nanotube orientation angles. Obtained results can be used to create new kinds of electronic devices.

1.	Massey M.K., Kotsialos A., Volpati D., Vissol-Gaudin E., Pearson C., Bowen L., Obara B., Zeze D.A., Groves C., Petty M.C. Evolution of Electronic Circuits using Carbon Nanotube Composites // Sci. Reports.-2016.-6.-32197.