Hi everyone,
Recently I have been conducting Dynamic Light scattering experiments in a micellar solution at 5 and gel at 37 degrees of Celsius with latex particles of diameter 190-500 nm. While conducting the experiments to extract the viscosity using DLS, the Z-average came out lower than the probe size ( I have conducted DLS of the same probes in water and it came out as expected). What can be the cause to this observation?
In the example given in one of the blogs of Malvern's the same has been reported where the Z-average of 100 nm latex particle has been reported as 78 nm whereas in water is 104 nm. What can be the reason for this observation? For reference:
https://www.malvernpanalytical.com/en/learn/knowledge-center/insights/what-is-the-maximum-viscosity-for-dls
I'm confused.
You are putting probe particles into a gel in order to use DLS to estimate the viscosity. However, to obtain the z-average, you have to specify the viscosity!
Shouldn't you be running the DLS experiment with an arbitrary viscosity and then, using the apparent z-average and the known probe size, calculate what the viscosity should be?
Yes John, that is what I am doing. I am confused as to why the Z-avg reading coming out lesser than the known probe size in a polymer solution!
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