Fluid Ferroelectric Filaments

Abstract

Freestanding slender fluid filaments of room‐temperature ferroelectric nematic liquid crystals are described. They are stabilized either by internal electric fields of bound charges formed due to polarization splay or by external voltage applied between suspending wires. The phenomenon is similar to those observed in dielectric fluids, such as deionized water, except that in ferroelectric nematic materials the voltages required are three orders of magnitudes smaller and the aspect ratio is much higher. The observed ferroelectric fluid threads are not only unique and novel but also offer measurements of basic physical quantities, such as the ferroelectric polarization and viscosity. Ferroelectric nematic fluid threads may have practical applications in nano‐fluidic micron‐size logic devices, switches, and relays.

Liquid Piezoelectric Materials: Linear Electromechanical Effect in Fluid Ferroelectric Nematic Liquid Crystals

“…FNLC 919 had two nematic phases, N and N 1 above the N F phase with the phase sequence in cooling as I 80 ○ C N 1 44 ○ C N 32 ○ C N F 8 ○ C Cr. FNLC 919 was studied by Yu et al [27] and Máthé et al [28] and the ferroelectric polarization was measured in free-standing threads at room temperature to be P o ≈ 3 • 10 −2 C m −2 . [28] This value was smaller than the P o ≈ 4.7 • 10 −2 C m −2 ,in in-plane field geometry (see Figure 3d) were measured here, likely due to the inhomogeneous field in the free-standing threads.…”

“…FNLC 919 was studied by Yu et al [27] and Máthé et al [28] and the ferroelectric polarization was measured in free-standing threads at room temperature to be P o ≈ 3 • 10 −2 C m −2 . [28] This value was smaller than the P o ≈ 4.7 • 10 −2 C m −2 ,in in-plane field geometry (see Figure 3d) were measured here, likely due to the inhomogeneous field in the free-standing threads. [28] Both FNLCs were contained between two, parallel glass plates having conducting indium tin oxide (ITO) sputtered in their inner surface, separated by a distance d, which was much smaller than the lateral dimensions (1 − 2 cm) of the planes.…”

Self-Consistent Explanation of the Untwist Alignment of Ferroelectric Nematic Liquid Crystals with Decreasing Cell Thickness and Deviation of the Surface Easy Axis Experimented upon Using the Brewster Angle Reflection Method

“…The FNLC substance used in this study was FNLC-919 (Merck) [9][10][11]17]. The original phase sequence is as follows [10]; Iso. 80 °C N1 44 °C N2 32 °C NF 8 °C Cryst.…”

“…The emergence of FNLCs challenges this classical understanding, thereby eliciting profound interest in FNLCs from the viewpoints of both material physics and the development of novel applications [8,9]. Recently, the first demonstration of converse piezoelectricity using FNLC substances that exhibit significant ferroelectricity at room temperature was published [10,11], and these results pave the way to the realization of flexible actuators that cannot be realized with solid materials. Studies on the unique electrical attributes of FNLCs have demonstrated that they can be distinguished from ordinary LCs using methods such as temperaturedependent dielectric constant measurements [6,12] and the detection of second harmonic generation [7,13].…”

“…This phenomenon eliminates the intrinsic π-twist alignment associated with the polar molecular alignment structure, thus giving rise to a planar alignment state. Studies towards obtaining the ferroelectric nematic phase (N F ) have focused on two LC materials, DIO and RM734, though in recent years other FNLCs have been reported such as FNLC-919 [9][10][11]17], which exhibits significant ferroelectricity at room temperature. In this study, we used FNLC-919 as it is easy to handle in experiments without a thermostat.…”