Ferroelectric nematic liquids with conics

Abstract

Spontaneous electric polarization of solid ferroelectrics follows aligning directions of crystallographic axes. Domains of differently oriented polarization are separated by domain walls (DWs), which are predominantly flat and run along directions dictated by the bulk translational order and the sample surfaces. Here we explore DWs in a ferroelectric nematic (NF) liquid crystal, which is a fluid with polar long-range orientational order but no crystallographic axes nor facets. We demonstrate that DWs in the absence of bulk and surface aligning axes are shaped as conic sections. The conics bisect the angle between two neighboring polarization fields to avoid electric charges. The remarkable bisecting properties of conic sections, known for millennia, play a central role as intrinsic features of liquid ferroelectrics. The findings could be helpful in designing patterns of electric polarization and space charge.

To Be or Not To Be Polar: The Ferroelectric and Antiferroelectric Nematic Phases

“…The high fluidity of the N F phase combined with its polar properties immediately caught the attention of scientists around the world due to not only its huge application potential but also its fundamental significance as a spontaneously ferroelectric fluid. The N F phase became one of the hottest topics in liquid crystal research. − Owing to the fluid nature of the N F phase, a uniform polarization direction can be obtained in large areasa key to realizing its application potential . However, the question arises whether the competitive interactions that drive the formation of the N F phase can also lead to other complex structures as is the case with the improper ferroelectric liquid crystal phases.…”

Rapid, solvent-minimized and sustainable access to various types of ferroelectric-fluid molecules by harnessing mechano-chemical technology

“…Such materials exhibit a wide spectrum of unique functional properties, including switchable polarization, large dielectric permittivity (410 000), large polarization density (44 mC cm À2 ), high nonlinear optical (NLO) activity (up to 10 pm V À1 ), low switching voltage, and high fluidity. Moreover, notable physical phenomena [9][10][11][12] and structures 13,14 are observed owing to the coupling between the polarization and fluidity. Since these discoveries, research into molecular design and synthesis of N F LCs and SmA F LCs has been launched 7,[15][16][17][18][19][20][21][22] toward a clear understanding of the underlying mechanism, 23,24 and development of state-of-the-art materials based on them.…”

New RM734-like fluid ferroelectrics enabled through a simplified protecting group free synthesis

“…The lower temperature nematic phase is now understood to be polar and is termed the ferroelectric nematic (N F ) phase. The N F phase is of special scientific interest [3][4][5][6][7][8][9][10][11][12] due to the presence of polar order in a fluid system coupled with a strong linear electrooptical response 13,14 and large polar domains. 15 The N F phase may also be aligned using existing alignment techniques originally developed for conventional nematics, 16 and potential applications are beginning to emerge, including photo-variable capacitors 17 and electrostatic actuators.…”