Effect of hydrophobic aerosil dispersions on the Goldstone mode dynamics in ferroelectric liquid crystal near the point of polarisation sign reversal

ABSTRACT

Broadband dielectric spectroscopy in the frequency range from 10⁻² Hz to 10⁷ Hz was used to study the effect of hydrophobic aerosil nanoparticles on the dynamics of the Goldstone mode in a ferroelectric liquid crystal near the point of spontaneous polarisation sign reversal. The obtained results show that an important role in the modification of the dynamics of the Goldstone mode and the phenomena at the point of spontaneous polarisation sign reversal is played not only by the presence of the nanoparticles themselves in the ferroelectric liquid crystal structure, but also the state of the surface of these nanoparticles. Similarly to the hydrophilic aerosil, the polarisation sign reversal temperature slightly decreases with the increase of the hydrophobic aerosil concentration. For small concentrations of hydrophobic aerosil, only slight changes in the dynamics of the Goldstone mode over the entire temperature range are detected. The observed deviations are due to the different influence of aerosil nanoparticles on the structure and dielectric properties of the tested composite caused by the specific surface treatment. The presence of the Goldstone mode above and below the point of polarisation sign reversal seems to confirm the model of two conformers with different structure and opposite dipole moments.

GRAPHICAL ABSTRACT

KEYWORDS:

• Dielectric spectroscopy
• hydrophobic aerosil nanoparticles
• Goldstone mode
• polarisation sign reversal
• ferroelectric liquid crystal

Disclosure statement

No potential conflict of interest was reported by the author(s).

Correction Statement

This article has been corrected with minor changes. These changes do not impact the academic content of the article.