Related Experiment Video
Updated: Jul 17, 2026
09:45
Separating Beads and Cells in Multi-channel Microfluidic Devices Using Dielectrophoresis and Laminar Flow
Published on: February 4, 2011
Electrostatic repulsion of positively charged vesicles and negatively charged objects
1Department of Chemical Engineering, University of Delaware, Newark, DE 19716, USA. Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104 USA. Groupe de Dynamique des Phases Condensees, Case 26, Universite de Mo.
Science (New York, N.Y.)
|July 20, 1999
Summary
Positively charged vesicles spontaneously form adhesion and repulsion zones when near negatively charged surfaces. This counterion aggregation mechanism explains interactions observed in surfactant vesicle experiments.
Area of Science:
- Colloid and surface science
- Biophysics
- Physical chemistry
Background:
- Mixed bilayer vesicles with positive surface charges interact with negatively charged surfaces.
- Understanding these interactions is crucial for explaining phenomena like vesicle adhesion and repulsion.
Purpose of the Study:
- To investigate the spontaneous partitioning of charged vesicles into distinct adhesion and repulsion zones.
- To elucidate the role of counterion aggregation in mediating these interactions.
Main Methods:
- Theoretical modeling of charged vesicle behavior near surfaces.
- Analysis of electrostatic interactions and counterion distribution within the vesicle.
Main Results:
- Positively charged vesicles spontaneously partition into adhesion and repulsion zones when interacting with negative surfaces.
- Internal negative counterions aggregate in the vesicle interior, creating a net negative charge in the repulsive zone.
- This mechanism demonstrates how oppositely charged objects can exhibit repulsion.
Conclusions:
- The spontaneous formation of adhesion and repulsion zones is driven by counterion aggregation within vesicles.
- This finding provides a mechanism to explain recent experimental observations in surfactant vesicle systems.
- The study highlights a fundamental principle of electrostatic interactions between charged objects.
Related Concept Videos
01:15Charging Conductors By Induction
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...
01:30Electric Field of Two Equal and Opposite Charges
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...
01:26Charge on a Conductor
An interesting property of a conductor in static equilibrium is that extra charges on the conductor end up on its outer surface, regardless of where they originate. Consider a hollow metallic conductor with a uniform surface charge density. Since the conductor itself is in electrostatic equilibrium, there should not be any electric field inside the conductor. Now, assume a Gaussian surface enclosing the hollow portion. Applying Gauss's law, the inner surface of the hollow conductor will not...
01:16Electric Field of Parallel Conducting Plates
Gauss' law relates the electric flux through a closed surface to the net charge enclosed by that surface. Gauss's law can be applied to find the electric field and the charge enclosed in a region depending on its charge distribution.
Consider a cross-section of a thin, infinite conducting plate having a positive charge. For such a large thin plate, as the thickness of the plate tends to zero, the positive charges lie on the plate's two large faces. Without an external electric field, the...
Consider a cross-section of a thin, infinite conducting plate having a positive charge. For such a large thin plate, as the thickness of the plate tends to zero, the positive charges lie on the plate's two large faces. Without an external electric field, the...
01:21DC Battery
A conductor needs to be a component of a path that creates a closed loop or full circuit to have a continuous current flowing through it. A current starts to flow if an electric field is created inside an isolated conductor that is not part of a full circuit. The conductor quickly develops a net positive charge at one end and a net negative charge at the other. These charges generate an electric field opposite the direction of the applied electric field, which reduces the current. Eventually,...
01:30The Electrical Double Layer
In the region where two bulk phases meet, an intricate electric charge distribution arises due to charge transfer, ion adsorption, molecular orientation, and charge distortion. This complex distribution is commonly referred to as the electrical double layer.When a solid electrode interfaces with ions in an electrolyte solution, the speed of electron transfer dictates the rates of oxidation and reduction. The electrode acquires a charge through the escape of atoms into the solution as cations or...