Which term is more apt in which case generally we use zetapotential for nanoparticles?
Dear Ravi,
As I know, both of them can be used for nanoparticles. But zeta-potential is used more often for nanoparticles. From the Zeta Potential, we can infer the surface charge. They are different physical Parameter and also have different Physical meaning. We talk about the surface Charge density more often than surface charge, You can get the answer from definition of them.
Dear Ravi,
As Wenyu Li said they both are parameter of nanoparticle . The study of zetapotential would rather tell you how well nanoparticles are stable in a dispersion medium certain value above (+30 mV) - (-30 mV) is considered to be a good value for zetapotential. The +ve and -ve value would be the surface charge of the nanoparticle. Zetapotential depends on viscosity of the dispersion medium and the mobility of nanoparticle in the dispersion medium. In more detail, The surface charge creates a stern potential over the nanoparticle in dispersion medium and a zetapoetntial layer is been formed due to the phase differences of the medium and the surface of nanoparticle. This accounts for stability study of the nanoparticle, a technique used to measure zetapotential is through Dynamic Light scattering. They both are different parameter but certain dependency is accounted in understanding the system (Colloidal dispersion of nanoparticle) as a whole.
Dear Ravi,
Application wise, both the terms are similar but technically they are different. We can simply say that zeta potential is a parameter to know the surface charge.
The term zeta potential is the the ratio of the potential difference on the shear plane in the electrical double layer of the interface (i.e. solid-liquid interface in case of nanopartices) and the electro-neutral region of the colloidal dispersion.
It is advisable to determine zeta potential instead of saying just the surface charge.
Dear Ravi Reddy,
I completely agree with Mr Mahesh Sawant, University of Mumbai.
Zeta potential is a technique to measure the surface charge of the particle for studying the stability of the formulation. Basically it is the scientific terminology used for electrokinetic potential and denoted by the greek letter Zeta. Therefore, in a very simple language zeta potential is the potential difference between the dispersion medium and the stationary layer of fluid attached to the dispersed particle hence zeta potential is a key indicator of the stability of colloidal dispersions.
I hope it helps you understand the difference between the two.
All the best!!!
Assume that you have dispersed your nanoparticles in a medium containing some ions (usually distilled and double distilled water has ions). If you take a single nanoparticle into account, it's surface has a charge which is nothing but "surface charge". Assume that the nanoparticle surface is negatively charged. Hence you get a "surface charge" with some negative value. Now as this nanoparticle is present in a solution containing ions, it's surface (negatively charged nanoparticle surface) attracts positive charged ions and these positively charged ions further attracts negatively charged ions and finally it forms a strongly bound inner "stern layer" and weakly bound outer layer (together it's called electric double layer). There will be a potential that exists at the boundary of this surface (it may also be assumed a difference between the potential of the outer layer and potential of the medium). This potential is called "Zeta potential". So, if we are dispersing the nanoparticles in deionized water, the surface zeta potential and the zeta potential should be same.
Please correct me if i am wrong.
Measured zeta potential value of TiO2 nanoparticles in DI is - 12. Does it mean the surface charge of TiO2 nanoparticle negative?
Positive counter-ions first attach to the negatively charged particle, forming a rigid layer called the Stern layer. The particle continues to attract more counter-ions but now these counter-ions are being repelled by other counter-ions in the vicinity and by the Stern layer itself. This second region is called the diffuse layer and together, both layers are referred to as the double layer.
Surface potential is the electrical potential between the surface of the particle and any point in the suspending liquid. The slip plane is where the Stern layer (Edit: not the Stern layer but the surrounding liquid) and diffuse layer meet and it is here the electrical potential is called the zeta potential.
Basically, the higher the absolute value of the zeta potential, the more stable the dispersion (particles are repelling each other). To aggregate the particles, you can change the zeta potential by changing the environment of the particles (pH, ions present, ionic strength, etc.) or by modifying the surface of the particles directly (active surface agents, polymers, etc.). A rule of thumb to aggregate the particles is to bring the zeta potential to between -25mV and +25mV. Hope it helps!
More info:
Google search this pdf -> Zeta Potential : A Complete Course in 5 Minutes
A more basic tutorial -> http://www.colloidal-dynamics.com/docs/CDElTut1.pdf
The zeta potential is the potential that is measured in Volts in the process of electrophoresis. If a nanoparticle in a dispersed system moves with electrophoresis to a positive electrode, its charge is negative and vice versa. Then before the zeta potential put a minus sign. But this is not a charge sign, but an indicator of the displacement of nanoparticles. The charge of a nanoparticle, like the zeta potential, occurs when a diffuse part of a bilayer is broken in the process of electrophoresis. The charge is measured in Coulombs. I ask the readers to look at a later discussion of this issue.
@ Dzmitry Shcharbin. You need to correct your definition of zeta potential. "Simplifying, zeta-potential is the value of surface charge" .
@ Dr.Purva Sanganeria Sethi. You need to correct your definition of zeta potential "Zeta potential is a technique to measure the surface charge of the particle" See my answer.
The Zeta Potential is the potential across the phase boundaries between solids and liquids. The magnitude of the zeta potential indicates the degree of electrostatic repulsion between adjacent charged particles in a dispersion. The ‘Zeta Potential’ term is used for determining the surface charge of nanoparticles in solutions. The zeta potential is also a key indicator of the stability of colloidal dispersions. Nanoparticles have a surface charge that attracts a thin layer of ions of opposite charge to the nanoparticle surface. When the potential is small, attractive forces may exceed this repulsion and the dispersion may break and flocculate. So, colloids with high zeta potential are electrically stabilized while colloids with low zeta potentials tend to coagulate or flocculate.
The Zeta Potential is related to the "surface charge", a property that all materials possess, or acquire, when suspended in a fluid. It is the electrical potential difference between the inner and outer surface of the dispersed phase in a colloid. "Surface charge" practically always appears on the particle surface when it is placed into a fluid.
Dear @Jiban Podder, actually, zeta potential is not "the potential across the phase boundaries between solids and liquids". It's the potential at the slipping plane, which is located somewhere in the diffuse part of the electrical double layer, as you may see in the picture posted earlier by @Daryl Lee. The action of electrolytes is observed primarily as the decreasing of the zeta potential due to the shrinking of the diffuse part of the electrical double layer.
The zeta potential (ZP) is a function of the surface charge which develops when any material is placed in a liquid. It is a very good index of the magnitude of the electrostatic repulsive interaction between particles. The ZP is commonly used to predict and control dispersion stability.
Can anyone tell me what is zeta potential? Why zeta potential needs?
The zeta potential (ZP) is a function of the surface charge which develops when any material is placed in a liquid. It is a very good index of the magnitude of the electrostatic repulsive interaction between particles. The ZP is commonly used to predict and control dispersion stability.
Zeta potential (electric potential) is a scalar quantity, which is the energy characteristic of the electrostatic field of the suspension. At any point of the field (see the figure Daryl Lee), the potential is equal to the potential energy of a single positive charge placed at that point.
The potential energy is equal to the work performed by the forces of electrostatic interaction acting on all the particles of the system, when moving from this configuration to a configuration for which the potential energy is applied equal to zero.
See also my answer before.The file is attached dictionary for students in colloid chemistry. The formula for calculating the kinetic or zeta potential is marked in red.
Dear @ Jiban Podder. You need to correct your definition of zeta potential "Surface charge is the electrical potential difference between the inner and outer surface of the dispersed phase in a colloid".
What are all the parameters which contributes to the surface charge of nanoparticles? Does it relates to the electrical conductivity of nanoparticles?
@Daryl Lee: The shear surface can sometimes approximately coincide with the boundary that separates the Stern layer from the diffuse layer, but in general, it separates the immobile layer (usually, Stern layer + part of the diffuse layer) that hydrodynamically moves with the particle from the surrounding medium.
I have a webinar that explains zeta potential very simply:
http://tinyurl.com/zetatube
Surface potential is the electrical potential between the surface of a particle and any point in the suspension. The zeta potential is where the Stern layer and diffuse layer cross each other and here the electrical potential named as the "zeta". Mohammad Hassan Shahavi
Dear Ravi Teja Reddy
The zeta potential is used to measure the magnitude of the electrical charge of the lipid bilayer and can be used to determine the charge stability of a dispersed system such as liposomes. In a folded capillary flow cell, an electric charge is applied through the sample to obtain a measurement.
A surface charge is a non-zero electric charge on a two-dimensional surface. On this 2-D surface, these electric charges are constrained, and it is used to define the charge distribution on the surface.
The charge that arises at the interface between a solid surface and its liquid medium is known as the zeta potential, kind of explanation with its application with lipid bilayer I suppose it sounds good
ZETASIZER and SURFACE CHARGES are non-identical parameters used to characterise a colloidal molecule or a nanoparticle.
Incase you want measure the zetasizer of nanoparticle in distilled water emulsions reccomendations that u subtract the electrostatic surface potential from 100 gives u an overall overview of the surrounding intrinsic shear plane
Your sample prepared for analysis should be in suspensions or colloidal as a function of pH to indirectly ascertain the charge of the colloidal suspension slipping surface therefore the zeta potential is not the surface charge
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