I need refractive index of silver nanoparticles for zeta potential and zeta sizer (edited) analysis. I would be grateful if you could suggest it
Mohammad Javad Golmohammadi A little research on Research Gate using the excellent Search function will provide your answer. For example:
https://www.researchgate.net/post/Title_Measuring_Zeta_Potential_of_Nanosheets_with_Unknown_Refractive_Index_and_Handling_High_Polydispersity_Index_in_Gel-Based_Nanosheets
You don't really need to worry about the refractive index for zeta potential. But it is a mandatory information when it comes to DLS. For silver, the RI is 0.135. :)
- The optical properties are not required for DLS if the robust intensity distribution is used (most robust parameters are the z-average and polydispersity index, PDI). They would only be required if an attempt to convert to a volume distribution was made. The conversion to number should never be attempted
- There are 2 parts to the RI - the real part and the imaginary (absorptive) part: RI = n - i.k
- The values of both n and k are wavelength dependent. The most commonly used laser in DLS is the He-Ne at 0.6328 microns
- The optical properties of silver and many other materials can be found in databases such as: https://refractiveindex.info/?shelf=main&book=Ag&page=Johnson where primary source material is quoted
- According to the above site (screen dump attached), the RI values for silver at 632.8 nm are: RI = 0.056 - i.4.28
This webinar (free registration required) may be of interest:
Silver colloids and invisible ink
https://www.malvernpanalytical.com/en/learn/events-and-training/webinars/W150902SilverColloidInvisibleInk.html
Camilla Borba Pereira Yes, for silver is 0.135 but for silver nanoparticle seems to be different
Quotation of an RI without a wavelength is practically meaningless especially for metals where the parameters can vary considerably. Couple of points:
- There are 2 parts to the RI - the real and imaginary parts. A real part of ~ 0.15 is seen at 340 nm. See attached
- On the surface (5 - 10 atomic layers) of material, silver is fully oxidized when in air or oxygen containing liquids (e.g. water). That is in the +1 oxidation state and not silver metal, Ag0. More information in the webinar noted above. Nanoparticles have considerable surface exposed to the environment
- The RI properties of the particle are not required for zeta potential/mobility determination or for the intensity distribution in DLS
- Badges
- Science topic
- Similar topics
- Mathematical Sciences
- Graphs