What does DLVO theory suggest?
What does DLVO theory suggest?
DLVO theory is a theory of colloidal dispersion stability in which zeta potential is used to explain that as two particles approach one another their ionic atmospheres begin to overlap and a repulsion force is developed.
How zeta potential can be determined with the help of streaming potential?
Electrophoretic light scattering (ELS) In contrast to streaming potential measurements no movement of the liquid is generated, but the movement of the particles is induced. Therefore, an electric field is applied and the electrophoretic mobility of particles is used to calculate the zeta potential.
What is nernst potential and zeta potential?
The terms Nernst potential and zeta potential are used in physical chemistry. The key difference between Nernst potential and Zeta potential is that Nernst potential is given for a biological cell or an electrochemical cell whereas zeta potential is given for a colloidal dispersion.
What is electrokinetic and zeta potential?
Zeta potential is a scientific term for electrokinetic potential in colloidal dispersions. In other words, zeta potential is the potential difference between the dispersion medium and the stationary layer of fluid attached to the dispersed particle.
What does DLVO stand for?
The DLVO theory is named after Derjaguin, Landau, Verwey, and Overbeek. It is the explanation of the stability of colloidal suspension. It describes the balance between two forces, electrostatic repulsion and van der Waals attraction.
What is secondary minimum?
Definition of secondary minimum : a sometimes very slight depression in the light curve of an eclipsing variable that occurs when the fainter of the two stars is eclipsed by the brighter — compare primary minimum.
How is zeta potential measured?
Zeta potential is measured by adding a solution to a cell that contains two gold electrodes. When a voltage is applied to the electrode, the particles will move toward the electrode with the opposite charge. A Doppler technique is used to measure the particle velocity as a function of voltage.
How do you interpret zeta potential?
Zeta can be used to predict the long-term stability of particles. For example, particles with zeta potentials larger than ±60 mV have excellent stability, where particles with zeta values between -10 mV and +10 mV, will experience rapid agglomeration unless they are sterically protected.
What is zeta potential measurement?
Zeta potential is a measure of the magnitude of the electrostatic or charge repulsion/attraction between particles and is one of the fundamental parameters known to affect stability.
What determines zeta potential?
The most important factor that affects zeta potential is the pH of the medium. Other factors include ionic strength, the concentration of any additives, and temperature. The significance of zeta potential is that its value can be related to the short- and long-term stability of emulsions.
Why is zeta potential measured?
The zeta potential (ZP) can be used to evaluate the charge stability of a disperse system, such as liposomes; it is used to quantify the magnitude of the electrical charge of the lipid bilayer. A measurement is taken by applying an electric charge across the sample in a folded capillary flow cell.
Which sole is used for protecting colloids?
The term Gold number is used in colloidal chemistry which is defined as the minimum amount of protective colloid (in milligrams) that prevents a color change from red to violet/blue (or to prevent the coagulation) of 10ml gold sol by the addition of 1ml of NaCl solution.
What is the DLVO theory of particle motion?
Overview. DLVO theory is a dispersion stabilizing theory in which zeta potential is used to explain that as two particles approach one another their ionic atmospheres begin to overlap and a repulsion force is developed. In this theory, two forces are considered to impact of colloidal stability: Van der Waals forces and Coulombic (Entropic)…
What is the zeta potential used for?
Using DLVO theory, it is possible to assess the stability of suspensions and emulsions by means of the zeta potential. The basis of DLVO is to use the sum of the repulsive force (VR – electrostatic BORN forces) and attractive (VA – van der WAALS forces) to calculate the particle interaction potential.
What is DLVO and how is it calculated?
The basis of DLVO is to use the sum of the repulsive force (VR – electrostatic BORN forces) and attractive (VA – van der WAALS forces) to calculate the particle interaction potential. In many cases, the zeta potential can be used directly as the criterion for assessing product quality.
What determines energy–distance curves according to the DLVO theory?
Energy–distance curves according to the DLVO theory [ 5, 6 ]. To ensure adequate colloid stability, Gmax has to be greater than 25 kT. The height of the maximum depends on the surface (or ζ) potential, electrolyte concentration, particle radius and Hamaker constant.
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