Related Experiment Video
Updated: Aug 15, 2025
07:03
Measuring Magnetically-Tuned Ferroelectric Polarization in Liquid Crystals
Published on: August 15, 2018
8.9K
Ferroelectric nematic droplets in their isotropic melt
Kelum Perera1,2, Rony Saha1,2, Pawan Nepal3
1Department of Physics, Kent State University, Kent OH, 44242, USA. ajakli@kent.edu.
Soft Matter
|January 4, 2023
Summary
Novel electromechanical effects in ferroelectric nematic liquid crystal droplets were observed. These droplets exhibit unique shapes, defect dynamics, and field-driven motion, revealing bound electric charges.
Area of Science:
- Materials Science
- Condensed Matter Physics
- Liquid Crystal Physics
Background:
- The isotropic to ferroelectric nematic liquid crystal transition has been theoretically studied for over a century.
- Experimental investigations into this transition and associated phenomena remain scarce.
Purpose of the Study:
- To experimentally investigate novel electromechanical effects in ferroelectric nematic liquid crystal droplets.
- To explore the behavior of these droplets coexisting with an isotropic melt under electric fields.
- To theoretically consider the observed phenomena and determine underlying physical parameters.
Main Methods:
- Experimental observation of ferroelectric nematic liquid crystal droplets in an isotropic melt.
- Application of weak and strong in-plane electric fields.
- Microscopic imaging to analyze droplet shape, defect dynamics, and motion.
- Theoretical analysis to determine polarization fields and bound charges.
Main Results:
- Droplets adopt flat, pancake-like shapes, constrained by sample thickness.
- A wing-shaped defect within droplets moves perpendicular to the electric field, extending and splitting at higher fields.
- Droplets exhibit field-independent drift velocity proportional to electric field amplitude.
- At fields above 1 mV μm-1, droplets deform and oscillate.
- Polarization fields and bound electric charges were identified due to polarization divergence around the defect.
Conclusions:
- The study reveals unique electromechanical responses of ferroelectric nematic liquid crystal droplets.
- The observed defect dynamics and droplet motion are directly linked to electric field interactions.
- The findings confirm the presence of bound electric charges arising from polarization divergences, offering insights into ferroelectric liquid crystal behavior.
Related Concept Videos
02:34Comparing Intermolecular Forces: Melting Point, Boiling Point, and Miscibility
44.8K
Intermolecular forces are attractive forces that exist between molecules. They dictate several bulk properties, such as melting points, boiling points, and solubilities (miscibilities) of substances. Molar mass, molecular shape, and polarity affect the strength of different intermolecular forces, which influence the magnitude of physical properties across a family of molecules.
Temporary attractive forces like dispersion are present in all molecules, whether they are polar or nonpolar. They...
Temporary attractive forces like dispersion are present in all molecules, whether they are polar or nonpolar. They...
44.8K
02:54Molecular and Ionic Solids
17.4K
Crystalline solids are divided into four types: molecular, ionic, metallic, and covalent network based on the type of constituent units and their interparticle interactions.
Molecular Solids
Molecular crystalline solids, such as ice, sucrose (table sugar), and iodine, are solids that are composed of neutral molecules as their constituent units. These molecules are held together by weak intermolecular forces such as London dispersion forces, dipole-dipole interactions, or hydrogen bonds, which...
Molecular Solids
Molecular crystalline solids, such as ice, sucrose (table sugar), and iodine, are solids that are composed of neutral molecules as their constituent units. These molecules are held together by weak intermolecular forces such as London dispersion forces, dipole-dipole interactions, or hydrogen bonds, which...
17.4K
02:39Phase Transitions: Melting and Freezing
12.6K
Heating a crystalline solid increases the average energy of its atoms, molecules, or ions, and the solid gets hotter. At some point, the added energy becomes large enough to partially overcome the forces holding the molecules or ions of the solid in their fixed positions, and the solid begins the process of transitioning to the liquid state or melting. At this point, the temperature of the solid stops rising, despite the continual input of heat, and it remains constant until all of the solid is...
12.6K
01:10Recrystallization: Solid–Solution Equilibria
1.2K
Recrystallization is a purification technique used to separate impurities from solid compounds. In this technique, no chemical reactions occur. Instead, it exploits physical properties only, specifically, the solubility differences between the desired compound and impurities, either at a single temperature or at different temperatures, and under other selected conditions. The solid-solution equilibrium (solubility equilibrium) of each component in the solution represents a binary phase...
1.2K
01:31Ferromagnetism
2.4K
Materials like iron, nickel, and cobalt consist of magnetic domains, within which the magnetic dipoles are arranged parallel to each other. The magnetic dipoles are rigidly aligned in the same direction within a domain by quantum mechanical coupling among the atoms. This coupling is so strong that even thermal agitation at room temperature cannot break it. The result is that each domain has a net dipole moment. However, some materials have weaker coupling, and are ferromagnetic at lower...
2.4K
01:28Induced Electric Dipoles
4.3K
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...
4.3K