Influence of SiO₂ nanoparticles on the dielectric properties and anchoring energy parameters of pure ferroelectric liquid crystal

Abstract

In this study, we have investigated the electrical and anchoring energy of ferroelectric liquid crystal (FLC) with the dispersion of SiO₂ nanoparticles (NPs). Due to their higher average spontaneous polarization and helical arrangement of FLC molecules, the molecules strongly interacted to SiO₂ NPs which increased the value of dielectric permittivity and anchoring energy parameters as demonstrated by the dielectric and electro-optic properties measurement. This two-dimensional array of molecules has been exploited through the study of dielectric permittivity and dielectric loss in presence of silica NPs from low frequency regime to high frequency region in deep smectic phase. In present work we reported dielectric and electro-optical parameters for pristine FLC and SiO₂+FLC composites (0.5% and 1.0% wt/wt concentrations of SiO₂ NPs). The dielectric permittivity and dielectric loss have been calculated from the measurement of capacitance and conductance with variation of frequency and concentration of NPs as well. The dispersion and polarization anchoring energy coefficients have been calculated from electro-optic properties measurement with the function of applied voltage for pure and SiO₂+FLC composites. The dielectric permittivity has increased with the dispersion of SiO₂ NPs in pure FLC matrix and relaxation frequency shifted towards high and low frequency region for low (0.5%) and high (1.0%) concentrations of NPs. The spontaneous polarization of SiO₂+FLC composites is increased as compared to pure FLC. The experimental results are explained on the basis of different intermolecular interactions arising between FLC molecules and SiO₂ NPs.

Graphical Abstract

Research Highlights

• The higher value of spontaneous polarization has observed for silica doped system in compared to the pure FLC system.

• The higher spontaneous polarization will be very beneficial from application point of view.

• The value of dispersion and polarization anchoring coefficient increases for fluorescent dye doped FLC mixtures in comparison to the pure FLC.

Keywords:

• Anchoring energy coefficients
• SiO2 nanoparticles
• ferroelectric liquid crystal
• dielectric permittivity
• dielectric loss
• spontaneous polarization

Acknowledgments

We are grateful to Prof. M. Srinivasulu, Manipal University Manipal and Prof. Purna Bose, Govt. VYTPG Autonomous College Durg, Chhattisgarh for support and help during this work.

Disclosure statement

The authors declare no conflicts of interest related to this article.