Thermotropic liquid crystal doped with silica, silica grafted with aniline (ANI@SiO2) and polyaniline (PANI@SiO2)

Nanoparticles dispersed in liquid crystals exhibit novel and intriguing properties, which make them suitable materials for displays and photonic applications. This paper reports on the impact of non-modified silica (SiO2), silica grafted with aniline (ANI@SiO2) and silica grafted with polyaniline (PANI@SiO2) nanoparticles on the physical parameters of 7CB liquid crystal. A slight change in the nematic-isotropic phase transition temperature was observed. The results from dielectric experiments revealed an increase in free ion concentration in the doped samples. By fitting a suitable equivalent electric circuit model to the experimental data, we demonstrate changes in the electro-physical parameters of the liquid crystal in the bulk and at the liquid crystal-metal electrode interface. Therefore, we were able to calculate the ion mobility and the diffusion constant. It was also demonstrated that the doping of 7CB with the above-mentioned nanoparticles increases the response time, thresholds, and viscosity.

Automated summary

This study investigates the effect of non-modified silica (SiO2), silica grafted with aniline (ANI@SiO2), and silica grafted with polyaniline (PANI@SiO2) nanoparticles on the physical parameters of 7CB liquid crystal. The results show an increase in free ion concentration in the doped samples, which affects the electro-physical parameters of the liquid crystal. By fitting an equivalent electric circuit model to the experimental data, the ion mobility and diffusion constant of the liquid crystal can be calculated. Furthermore, the doping of 7CB with the aforementioned nanoparticles increases the response time, thresholds, and viscosity.