I want to measure the charge on the particles in the solutions using zetasizer, but the experiment needs R.I and absorbance co-efficient to be conducted, but i cant find the stated valued for the specific solution, how to process the experiment?
Further, its a colloidal solution , so is it possible to measure charge in such cases?
Zeeshan Ur Rehman
There are a lot of confusing statements in your question. A true solution does not contain particles... You cannot measure the zeta potential of a solution. Do you mean suspension?
Zeta potential (ZP) is not the charge on the particle in suspension. It's the value of the potential at the slipping plane (effectively where the particle interacts with other particles and is some distance from the surface of the particle). ZP is a holistic property dependent on both the particle itself but also on the properties of the continuous phase, the most important being pH, concentration, and multivalent ion concentration.
ZP is not measured directly. You measure the movement of the particles in the electrical or acoustic field and infer the ZP with the appropriate theorem. You do not need the particle RI and absorption for a measurement as you're measuring movement. The RI of the continuous phase is needed in order to correct for the deflection of the laser (in a electrophoretic measurement). You can easily measure this (Abbe refractometer) but it's likely to be 1.33 (water) in the dilute measurement conditions.
Many systems can obtain particle size by measuring the movement (Brownian motion) in the absence of an electrical field. In this case the particle's optical properties would be needed for the usually ill-advised conversion of intensity to volume or number (never!).
I'm interested in your 'colloidal starch' as many starches are in the 1 - 20 micron region. I assume your colloidal material is transparent to the eye.
Kindly check https://www.researchgate.net/publication/227720943_Zeta_Potential_and_Pasting_Properties_of_Phosphorylated_or_Crosslinked_Rice_Starches
Zeta potential is a scientific term for electrokinetic potential in colloidal dispersions. In the colloidal chemistry literature, it is usually denoted using the Greek letter zeta (ζ), hence ζ-potential. The usual units are volts (V) or millivolts (mV). From a theoretical viewpoint, the zeta potential is the electric potential in the interfacial double layer (DL) at the location of the slipping plane relative to a point in the bulk fluid away from the interface. In other words, zeta potential is the potential difference between the dispersion medium and the stationary layer of fluid attached to the dispersed particle.
https://en.m.wikipedia.org/wiki/Zeta_potential
The zeta potential is a key indicator of the stability of colloidal dispersions. The magnitude of the zeta potential indicates the degree of electrostatic repulsion between adjacent, similarly charged particles in a dispersion. For molecules and particles that are small enough, a high zeta potential will confer stability, i.e., the solution or dispersion will resist aggregation. When the potential is small, attractive forces may exceed this repulsion and the dispersion may break and flocculate. So, colloids with high zeta potential (negative or positive) are electrically stabilized while colloids with low zeta potentials tend to coagulate or flocculate https://en.m.wikipedia.org/wiki/Zeta_potential
Yes, in my case the values comes out near about Zero (up to 3). How to increase the values of this solution (i mean suspension), bcz we want to use that starch solution as polyelectrolyte for coating purposes.
thank you
Hi Zeeshan Ur Rehman , Concerning your question about the material properties for the measurement with the Zetasizer, these should not matter for zeta potential. You can check that yourself by editing a record and changing the material refractive index and absorption to observe. See the paragraph "Try out a value and see the effect" in https://www.materials-talks.com/blog/2014/08/05/faq-how-important-are-refractive-index-absorption-for-nanoparticles/ for a description on editing records.
there are different starch derivatives with ionic charge (polyelectrolytes), dissolved amylose is nonionic.
Suggest you first read about chemistry, properties of starch and its derivatives.
The best way is to use Ultrasound, you can have a look at Conference Paper Colloid Vibration Potential for Imaging in Engineering and Medicine
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