Browse
Submit Data
Databases
API
Help

Dataset Information

0 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

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 (N_F) 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.

SUBMITTER: Kumari P

PROVIDER: S-EPMC9918734 | biostudies-literature | 2023 Feb

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Publications

Ferroelectric nematic liquids with conics.

Kumari Priyanka P Basnet Bijaya B Wang Hao H Lavrentovich Oleg D OD

Nature communications 20230210 1

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 (N<sub>F</sub>) liquid crystal, which is a fluid with polar long-range orientational order but no crystallographic axes nor facets. We demo ...[more]

PMID: 36765061

Similar Datasets

Polarization patterning in ferroelectric nematic liquids via flexoelectric coupling.

Project description:The recently discovered ferroelectric nematic liquids incorporate to the functional combination of fluidity, processability and anisotropic optical properties of nematic liquids, an astonishing range of physical properties derived from the phase polarity. Among them, the remarkably large values of second order optical susceptibility encourage to exploit these new materials for non-linear photonic applications. Here we show that photopatterning of the alignment layer can be used to structure polarization patterns. To do so, we take advantage of the flexoelectric effect and design splay structures that geometrically define the polarization direction. We demonstrate the creation of periodic polarization structures and the possibility of guiding polarization by embedding splay structures in uniform backgrounds. The demonstrated capabilities of polarization patterning, open a promising new route for the design of ferroelectric nematic based photonic structures and their exploitation.

| S-EPMC10213025 | biostudies-literature

Emergent Ferroelectric Nematic and Heliconical Ferroelectric Nematic States in an Achiral "Straight" Polar Rod Mesogen.

Project description:Ferroelectric nematic liquid crystals (NFLCs) are distinguished by their remarkable polarization characteristics and diverse physical phenomena, sparking significant interest and excitement within the scientific community. To date, over 150 NFLC molecules are developed; however, there are no reports regarding straight linear polar molecules with a parallel alignment of the permanent dipole moment and the molecular axis. The straight polar mesogen nBOE exhibits an enantiotropic NF phase with a wide temperature window (up to 100 K) despite having a longer alkyl chain (up to n = 6) than the critical alkyl chain length of conventional models. Interestingly, nBOE with a medium-length alkyl chain displays an exotic phase sequence of NF-HCNF-SmXF during the elimination of positional displacement among adjacent molecules. Furthermore, the reflective color modulation of the HCNFLC over the entire VIS-NIR spectral regime by ultralow E-field (up to 0.14 V µm-1) is demonstrated.

| S-EPMC11633337 | biostudies-literature

Electrically activated ferroelectric nematic microrobots.

Project description:Ferroelectric nematic liquid crystals are fluids exhibiting spontaneous electric polarization, which is coupled to their long range orientational order. Due to their inherent property of making bound and surface charges, the free surface of ferroelectric nematics becomes unstable in electric fields. Here we show that ferroelectric liquid bridges between two electrode plates undergo distinct interfacial instabilities. In a specific range of frequency and voltage, the ferroelectric fluid bridges move as active interacting particles resembling living organisms like swarming insects, microbes or microrobots. The motion is accompanied by sound emission, as a consequence of piezoelectricity and electrostriction. Statistical analysis of the active particles reveals that the movement can be controlled by the applied voltage, which implies the possible application of the system in new types of microfluidic devices.

| S-EPMC11336208 | biostudies-literature

Ferroelectric Nematic Liquid Crystals Showing High Birefringence.

Project description:High birefringence nematic liquid crystals are particularly demanded for adaptive optics applications in the infrared spectrum because it enable a thinner cell gap for achieving fast response time and improved diffraction efficiency. The emerging ferroelectric nematic liquid crystals have attracted widespread interest in soft matter due to their unique combination of ferroelectricity and fluidity. However, the birefringence, which is one of the most important optical parameters in electro-optic devices, is not large enough (<0.25) in most ferroelectric nematic materials. Here, a polar liquid crystal molecule library containing more than 60 molecules with a highly rigid and fluorinated nature is developed. The introduction of triple bonds constructs a long π-electron conjugated mesogen skeleton, significantly improving the birefringence of polar liquid crystal phases. The birefringence and dispersion properties are systematically studied, demonstrating a strong dependence on chemical structures and the type of polar phases. Furthermore, through multi-component mixing, polar liquid crystal mixtures with ultra-wide temperature range and excellent stability at or near room temperature are obtained. They possess much higher birefringence than the existing ferroelectric liquid crystal materials. The unique combination of high birefringence and fluidic ferroelectricity is expected to promote the application of polar liquid crystals in electro-optic technologies.

| S-EPMC11884546 | biostudies-literature

Nematic and Smectic Phases with Proper Ferroelectric Order.

Project description:A material showing a sequence of three ferroelectric liquid crystalline phases below the paraelectric nematic phase is synthesized and studied. The polar order of molecules appearing due to the dipole-dipole interactions in the ferroelectric nematic, NF, phase is preserved also in the smectic phases: orthogonal SmAF and tilted SmCF. The ferroelectric ground state of both smectic phases is confirmed by their second harmonic generation (SHG) activity and polarization switching. In the SmCF phase the polarization becomes oriented to the electric field by decreasing the tilt angle to zero. Although both smectic phases are ferroelectric in nature, their dielectric response is found to be very different.

| S-EPMC11744557 | biostudies-literature

Periodic splay Freedericksz transitions in a ferroelectric nematic.

Project description:Electric field-induced splay of molecular orientation, called the Fréedericksz transition, is a fundamental electro-optic phenomenon in nonpolar nematic liquid crystals. In a ferroelectric nematic NF with a spontaneous electric polarization P , the splay is suppressed since it produces bound electric charges. Here, we demonstrate that an alternating current (ac) electric field causes three patterns of NF polarization. At low voltages, P oscillates around the field-free orientation with no stationary deformations. As the voltage increases, the polarization acquires stationary distortions, first splay and twist in a stripe pattern and then splay and bend in a square lattice of +1 and -1 defects. In all patterns, P oscillates around the stationary orientations. The stationary bound charge is reduced by a geometrical "splay cancellation" mechanism that does not require free ions: the charge created by splay in one plane is reduced by splay of an opposite sign in the orthogonal plane.

| S-EPMC11806116 | biostudies-literature

Antiferroelectric Order in Nematic Liquids: Flexoelectricity Versus Electrostatics.

Project description:The recent discovery of ferroelectric nematic liquid crystalline phases marks a major breakthrough in soft matter research. An intermediate phase, often observed between the nonpolar and the ferroelectric nematic phase, shows a distinct antiferroelectric response to electric fields. However, its structure and formation mechanisms remain debated, with flexoelectric and electrostatics effects proposed as competing mechanisms. By controlling the magnitude of electrostatic forces through ion addition in two representative ferroelectric nematic materials, it is shown that the primary mechanism for the emergence of antiferroelectric order is the flexoelectric coupling between electric polarization and splay deformation of the nematic director. The addition of ions significantly expands the temperature range over which the antiferroelectric phase is observed, with this range increasing with increasing ion concentration. Polarizing optical microscopy studies and second harmonic generation (SHG) microscopy reveal the splayed structure modulated in 2D, while SHG interferometry confirms its antiferroelectric character. The model previously used to describe pretransitional behavior is extended by incorporating the electrostatic contribution of ions. The model shows qualitative agreement with the experiments, accurately reproducing the phase diagram and temperature-dependent evolution of the modulation period of the observed structure.

| S-EPMC11884549 | biostudies-literature

On the molecular origins of the ferroelectric splay nematic phase.

Project description:Nematic liquid crystals have been known for more than a century, but it was not until the 60s-70s that, with the development of room temperature nematics, they became widely used in applications. Polar nematic phases have been long-time predicted, but have only been experimentally realized recently. Synthesis of materials with nematic polar ordering at room temperature is certainly challenging and requires a deep understanding of its formation mechanisms, presently lacking. Here, we compare two materials of similar chemical structure and demonstrate that just a subtle change in the molecular structure enables denser packing of the molecules when they exhibit polar order, which shows that reduction of excluded volume is in the origin of the polar nematic phase. Additionally, we propose that molecular dynamics simulations are potent tools for molecular design in order to predict, identify and design materials showing the polar nematic phase and its precursor nematic phases.

| S-EPMC8367997 | biostudies-literature

Fluid fibers in true 3D ferroelectric liquids.

Project description:We demonstrate an exceptional ability of a high-polarization 3D ferroelectric liquid to form freely suspended fluid fibers at room temperature. Unlike fluid threads in modulated smectics and columnar phases, where translational order is a prerequisite for forming liquid fibers, recently discovered ferroelectric nematic forms fibers with solely orientational molecular order. Additional stabilization mechanisms based on the polar nature of the mesophase are required for this. We propose a model for such a mechanism and show that these fibers demonstrate an exceptional nonlinear optical response and exhibit electric field-driven instabilities.

| S-EPMC10990086 | biostudies-literature

Electric field-induced interfacial instability in a ferroelectric nematic liquid crystal.

Project description:Studies of sessile droplets and fluid bridges of a ferroelectric nematic liquid crystal in externally applied electric fields are presented. It is found that above a threshold, the interface of the fluid with air undergoes a fingering instability or ramification, resembling to Rayleigh-type instability observed in charged droplets in electric fields or circular drop-type instabilities observed in ferromagnetic liquids in magnetic field. The frequency dependence of the threshold voltage was determined in various geometries. The nematic director and ferroelectric polarization direction was found to point along the tip of the fingers that appear to repel each other, indicating that the ferroelectric polarization is essentially parallel to the director. The results are interpreted in connection to the Rayleigh and circular drop-type instabilities.

| S-EPMC10147939 | biostudies-literature

OmicsDI is part of the ELIXIR infrastructure

OmicsDI is an Elixir interoperability service. Learn more ›

Tweets

OmicsDI Databases

PRIDE
PeptideAtlas
MassIVE
JPOST Repository
Physiome Model Repository

EGA
EVA
ENA
LINCS
PAXDB
Cell Collective

MetaboLights
Metabolomics Workbench
MetabolomeExpress
GNPS
BioModels
FAIRDOMHub

ArrayExpress
dbGaP
ExpressionAtlas
GEO
NODE

Information

Databases
Help
API
Contact us
Code on GitHub
Terms of use
Submit Data