Molecular and collective modes in ferroelectric liquid crystals studied by dielectric spectroscopy

Spontaneous polarization and dielectric relaxation dynamics of ferroelectric liquid crystals derived from 2(S)-[2(S)-ethylhexyolxy] propionic acid and its (S, R)-diastereomer

“…For FLC compounds with a high degree of Ps, another type of collective dielectric process, known as the domain mode (DM), is a result of Ps under certain conditions. In addition, a new domain structure with different periodicity in the bulk and at the surface has been proposed [9,11,14,15]. Moreover, at certain temperatures, the FLCs exhibit two molecular processes in a high-frequency region (1 MHz and greater).…”

Dielectric spectroscopy of a smectic liquid crystal

“…The dielectric constant and loss for the present FLC material were determined from a fitting of the complex dielectric permittivity [14,16] using…”

“…In the MHz region, the FLC exhibits two high-frequency molecular processes corresponding to the molecular rotation of the molecules around the long and short axes. These processes are present in all liquid crystalline phases and have been well reported [14][15][16][17].…”

“…As usual, the signature of the Smode is indicated a few degrees above and below the SmC*-SmA-transition temperature [8,13]. It is also well known that in the SmC* phase the S-mode can be detected only near the SmA-SmC* phase transition and when the G-mode is suppressed by a dc bias-field [12,14,16]. Otherwise it is overwhelmed by the G-mode.…”

“…In FLCs with high spontaneous polarization (P s ), the structural parameters can be influenced by P s under certain conditions (a new domain structure with different periodicity in the bulk and at the surface has been proposed). This collective dielectric process is known as the domain mode (DM) [9,10,14]. In the MHz region, the FLC exhibits two high-frequency molecular processes corresponding to the molecular rotation of the molecules around the long and short axes.…”