Dielectric properties of liquid crystalline composites doped with nano-dimensional fragments of shungite carbon

ABSTRACT

A cholesteric liquid crystal (CLC) – cholesteryl tridecylate (X-20) was doped with nanoparticles of shungite carbon (Sh) to effectively improve some physicochemical properties of the CLC matrix for the further use in electronic devices. The influence of Sh (concentration of 0.005 and 0.02 wt. %) on phase transition temperatures of X-20 was studied. Addition of 0.005 wt. % of Sh shifts phase transition temperatures upward, while the concentration increase to 0.02 wt. % leads to the opposite effect. These data were taken into account during the study of dielectric properties in different phase states. The dielectric properties were studied in the frequency range from 20 Hz to 10 MHz. Only for the system X-20/Sh (0.02 wt. %), dispersion of the dielectric permittivity was observed. The dispersion was caused by the appearance of additional relaxation processes and it was substantially more extended than the classical Debye theory suggests. The results of the research show that the ‘CLC – Sh nanoparticles’ composites can be used as promising materials to increase the efficiency of radio electronics devices.

Graphical Abstract

KEYWORDS:

• Liquid crystals
• shungite carbon
• nanocomposites
• dielectric spectroscopy
• dispersion

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

The work was supported by the programme of the Ministry of Education and Science of the Russian Federation [Grant No. 16.1037.2017/4.6] and the Russian Foundation for Basic Research [Grant No. 18-29-19150_mk] – for Ivanovo State University; partially by the Russian Foundation for Basic Research [Grant No. 18-07-00727 and 17-47-500757] and the programme of the President of the Russian Federation [Grant No. MK-3120.2018.9] – for Moscow Region State University.