I have a colloidal solution of Iron oxide with PSS as capping agent dissolved in water. For such solution, what should be chosen in the material and dispersion section of the sample properties of the instrument. I am expecting the particle size to be in few micron range and hence, RI and absorption values may play a role as well. Where to retrieve the required values?
This question has been answered many times before on ResearchGate. Look for posts by Ulf Nobbmann in particular. You only need the RI of the continuous phase for an intensity size distribution. You need to carry out a Stokes' Law calculation. Iron oxide has a high density (~ 5.5 g/cm3) and will quickly sediment in aqueous media thus ruling out the DLS methodology. Such a sample is more suited to laser diffraction. 'Few microns' is neither 'nano' nor colloidal nor appropriate for DLS.
See for example:
http://www.materials-talks.com/blog/2017/01/23/intensity-volume-number-which-size-is-correct/
http://www.materials-talks.com/blog/2017/01/23/intensity-volume-number-which-size-is-correct/
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