Related Experiment Video
Updated: Jun 28, 2025
08:06
Merging Ion Concentration Polarization between Juxtaposed Ion Exchange Membranes to Block the Propagation of the Polarization Zone
Published on: February 23, 2017
8.5K
Electrode process of mobile ions in generating space-charge polarization
Atsushi Sawada1, Takaaki Manaka1
1Department of Electrical and Electronic Engineering, Tokyo Institute of Technology, 2-12-1, O-okayama, Meguro-ku, Tokyo 152-8552, Japan.
Physical Review. E
|April 18, 2024
Summary
This study confirms that space-charge polarization, driven by mobile ions near electrodes, creates macroscopic dipole moments. This phenomenon significantly impacts the dielectric properties of electrolytic cells, offering insights into material dielectric constants.
Area of Science:
- Electrochemistry
- Materials Science
- Physical Chemistry
Background:
- Macroscopic dipole moments in electrolytic cells affect dielectric properties.
- Dielectric spectroscopy quantifies these dipole moments.
- Understanding polarization mechanisms is crucial for materials science.
Purpose of the Study:
- Analyze dielectric spectra in low-frequency regions for dilute electrolytic cells.
- Differentiate between space-charge polarization and diffuse double layers.
- Investigate the formation process and contribution of space-charge polarization to dielectric properties.
Main Methods:
- Dielectric spectroscopy analysis of dilute electrolytic cells.
- Application of the Poisson-Nernst-Planck model.
- Characterization using effective dielectric constant and kinetic parameters.
Main Results:
- Space-charge polarization arises from mobile ions replacing solvent molecules at electrode surfaces.
- Distinct kinetic parameters and effective dielectric constants characterize space-charge polarization versus diffuse double layers.
- Experimental confirmation of macroscopic dipole moment formation via space-charge polarization.
Conclusions:
- Space-charge polarization is experimentally confirmed as a key mechanism for generating macroscopic dipole moments.
- This polarization directly contributes to the dielectric constant of materials.
- The findings provide a deeper understanding of dielectric phenomena in electrolytic systems.
Related Concept Videos
03:00Electrolysis
26.3K
In a galvanic cell, the electrical work is done by a redox system on its surroundings as electrons produced by the spontaneous redox reactions are transferred through an external circuit. Alternatively, an external circuit does work on a redox system by imposing a voltage sufficient to drive an otherwise nonspontaneous reaction in a process known as electrolysis. For instance, recharging a battery involves the use of an external power source to drive the spontaneous (discharge) cell reaction in...
26.3K
01:29Potential Due to a Polarized Object
398
A neutral atom consists of a positively charged nucleus surrounded by a negatively charged electron cloud. When placed in an external electric field, the external electric force pulls the electrons and nucleus apart, opposite to the intrinsic attraction between the nucleus and the electrons. The opposing forces balance each other with a slight shift between the center of masses of the nucleus and the electron cloud, resulting in a polarized atom. On the other hand, a few molecules, like water,...
398
01:15Charging Conductors By Induction
7.7K
The Earth is a good conductor of electricity, and it is so big that it can be considered an infinite source or sink of charges. It can easily exchange charges with any matter.
Generally, conductors like metals do not allow any excess charge to be present on them. Any excess charge added to metals easily flows away, for example, when a metal is placed on the Earth. This process is called earthing.
However, conductors can be charged by a process called induction. For example, consider charging a...
Generally, conductors like metals do not allow any excess charge to be present on them. Any excess charge added to metals easily flows away, for example, when a metal is placed on the Earth. This process is called earthing.
However, conductors can be charged by a process called induction. For example, consider charging a...
7.7K
01:31Dielectric Polarization in a Capacitor
4.7K
The presence of a dielectric medium in a capacitor not only changes the voltage and capacitance but also affects the electric field. In general, dielectrics can be of two types: polar and nonpolar. In a polar dielectric, the positive and negative charges in the molecules are separated by a distance and hence have a permanent dipole moment. In contrast, no such charge separation exists in a nonpolar dielectric, however the nonpolar molecules get polarized in the presence of an external electric...
4.7K
01:21Electrochemical Gradient and Channel Proteins: An Overview
2.2K
An electrochemical gradient is a fundamental concept in biology and chemistry. It regulates the movement of ions across cell membranes. This movement is influenced by two factors:
The electrical gradient: The electrical gradient across cell membranes refers to the difference in electric charge between the inside and outside of a cell. This difference drives the movement of ions towards or away from the cells. For instance, if the inside of the cell is more negatively charged relative to...
The electrical gradient: The electrical gradient across cell membranes refers to the difference in electric charge between the inside and outside of a cell. This difference drives the movement of ions towards or away from the cells. For instance, if the inside of the cell is more negatively charged relative to...
2.2K
01:26What is an Electrochemical Gradient?
110.1K
Adenosine triphosphate, or ATP, is considered the primary energy source in cells. However, energy can also be stored in the electrochemical gradient of an ion across the plasma membrane, which is determined by two factors: its chemical and electrical gradients.
The chemical gradient relies on differences in the abundance of a substance on the outside versus the inside of a cell and flows from areas of high to low ion concentration. In contrast, the electrical gradient revolves around an...
The chemical gradient relies on differences in the abundance of a substance on the outside versus the inside of a cell and flows from areas of high to low ion concentration. In contrast, the electrical gradient revolves around an...
110.1K