Related Experiment Video
Updated: Mar 17, 2026
07:03
Measuring Magnetically-Tuned Ferroelectric Polarization in Liquid Crystals
Published on: August 15, 2018
9.3K
DH(*) in chiral smectics under electric field.
C Meyer1, C Rabette2, P Gisse2
1Laboratoire de Physique des Systèmes Complexes, Université de Picardie Jules Verne, 33 rue Saint-Leu, 80039, Amiens, France. claire.meyer@u-picardie.fr.
The European Physical Journal. E, Soft Matter
|July 29, 2016
Summary
Researchers studied double helices (DH) in liquid crystals with chiral dopants. They found that electric fields can shrink DH structures and reduce their pitch, mimicking temperature changes.
Area of Science:
- Liquid Crystal Physics
- Chirality Studies
- Soft Matter Science
Background:
- Double helices (DH) form in liquid crystals doped with chiral molecules within the N-SmA temperature range.
- Investigated systems included both left-handed and right-handed chiral dopants.
Purpose of the Study:
- To investigate the behavior of double helices (DH) in chiral-doped liquid crystals.
- To correlate the handedness of DH with the chirality of the mixture.
- To study the effect of AC electric fields on DH structure and pitch.
Main Methods:
- Experimental investigation of liquid crystal compounds.
- Statistical analysis of double helix handedness.
- Application of gradually increasing AC electric fields.
Main Results:
- A correlation was observed between the handedness of DH and the chirality of the mixture.
- Applying an AC electric field caused the cylinder circumscribing the DH to shrink.
- This electric field-induced shrinking was accompanied by a reduction in the DH's pitch.
Conclusions:
- The handedness of double helices in chiral-doped liquid crystals is influenced by mixture chirality.
- AC electric fields can induce structural changes in double helices, including pitch reduction.
- The observed electric field effect on DH pitch is analogous to temperature-induced changes.
Keywords:
Soft Matter: Liquid crystals
Related Concept Videos
01:30Electric Field of Two Equal and Opposite Charges
7.4K
Atoms generally contain the same number of positively and negatively charged particles, protons, and electrons. Hence, they are electrically neutral. However, the centers of the positive and negative charges do not always coincide. In such a scenario, the electric field of an atom may not be zero.
A separation of the positive and negative charges can lead to a weak, remnant effect of the positive and negative charges. The expectation is that the more the distance between the positive and...
A separation of the positive and negative charges can lead to a weak, remnant effect of the positive and negative charges. The expectation is that the more the distance between the positive and...
7.4K
01:23Electric Field of a Charged Disk
3.5K
The simplest case of a surface charge distribution is the uniformly charged disk. Calculating its electric field also helps us calculate the electric field of a large plane of charge.
The system's symmetry is in the cylindrical directions across the plane of the charge. As a result, the electric fields created by various surface charge elements nullify each other in the direction parallel to the surface. Thereby, the resulting electric field is perpendicular to the plane. Since the disk is...
The system's symmetry is in the cylindrical directions across the plane of the charge. As a result, the electric fields created by various surface charge elements nullify each other in the direction parallel to the surface. Thereby, the resulting electric field is perpendicular to the plane. Since the disk is...
3.5K
02:30Chirality at Nitrogen, Phosphorus, and Sulfur
7.3K
Chirality is most prevalent in carbon-based tetrahedral compounds, but this important facet of molecular symmetry extends to sp3-hybridized nitrogen, phosphorus and sulfur centers, including trivalent molecules with lone pairs. Here, the lone pair behaves as a functional group in addition to the other three substituents to form an analogous tetrahedral center that can be chiral.
A consequence of chirality is the need for enantiomeric resolution. While this is theoretically possible for all...
A consequence of chirality is the need for enantiomeric resolution. While this is theoretically possible for all...
7.3K
01:27π Electron Effects on Chemical Shift: Overview
1.9K
An applied magnetic field causes loosely bound π-electrons in organic molecules to circulate, producing a local or induced diamagnetic field over a large spatial volume. As the molecules tumble in solution, the field generated by π-electrons in spherical substituents results in a zero net field. However, the net field generated by π-electrons in non-spherical substituents is not zero. The effect of this induced field depends on the orientation of the molecule with respect to B0,...
1.9K
01:28Induced Electric Dipoles
5.0K
A permanent electric dipole orients itself along an external electric field. This rotation can be quantified by defining the potential energy because the external torque does work in rotating it. Then, the potential energy is minimum at the parallel configuration and maximum at the antiparallel configuration. While the former is a stable equilibrium, the latter is an unstable equilibrium.
Since the absolute value of potential energy holds no physical meaning, its zero value can be chosen as per...
Since the absolute value of potential energy holds no physical meaning, its zero value can be chosen as per...
5.0K
01:22Electric Field of a Non Uniformly Charged Sphere
2.4K
Gauss's law states that the electric flux through any closed surface equals the net charge enclosed within the surface. This law is beneficial for determining the expressions for the electric field for a particular charge distribution if the electric flux is known.
Consider a non-uniformly charged sphere, for which the density of charge depends only on the distance from a point in space and not on the direction. Such a sphere has a spherically symmetrical charge distribution. Here, the electric...
Consider a non-uniformly charged sphere, for which the density of charge depends only on the distance from a point in space and not on the direction. Such a sphere has a spherically symmetrical charge distribution. Here, the electric...
2.4K