The mode of 2600 nanometers causes suspicion. I recommend to filter your solution cyclically five times through 200 nanometers filter. It is standard procedure for dust removal from water solutions in DLS.
Exactly. Dust is your worst enemy. I use Anatop filters with 20nm (twenty) pore size when I'm measuring micelles. Use many short measurements instead of one long one, so that the influence of an occasional dust particle can be eliminated before analysis. When dust is eliminated, the photon count rate will be very stable.
I support Colleagues.
And still I recommend to look at literature on this matter. SDS - classical surfactant and its micellts in water has been investigated in details, including DLS.
Hello Mitesh,
There is an application note about micelle characterization using the Zetasizer Nano S on the Malvern website (link below) which you may find useful. This discusses the use of Dynamic Light Scattering for this kind of analysis, as well as the determination of Critical Micelle Concentration.
http://www.malvern.com/en/support/resource-center/application-notes/AN101104SurfactantMicelleCharacterization.aspx
Hi Mitesh, First the article is about polystyrene particles dispersed using SDS and not the micellization of SDS. SDS help dispersed the polystyrene particles. It is difficult to measure CMC of ionic surfactants using light scattering methods due to multiple scattering. You should contact Malvern and ask the same question directly. I think this is too late for you.
Alexander Bulavchenko
Our studies show that micelles of ionic surfactants and DDS are not classical micelles. The formation of micelles accompanies the fluctuation phase transition liquid-liquid. Water fluctuations are detected by the DLS method. With this method, you will measure the hydration radius of micelles when you destroy the water nanoclusters involved in the phase transition, adding a sufficient amount of inorganic electrolyte. Micelle without electrolyte has dual properties. She is oscillating. So far, we can say that contact (without water) and hydrated (with water) micelles are formed. Therefore, you get gold nanoparticles in AOT micelles and do not refer to our patent of the Russian Federation 2369466. Nanoparticles can also be obtained in micellar solutions of cationic surfactants, although the gold ion cannot get into the micelle according to the classical model. You can read about it in
https://www.researchgate.net/publication/274011380_Liquid_Polyamorphous_Transition_and_Self-Organization_in_Aqueous_Solutions_of_Ionic_Surfactants
https://www.researchgate.net/publication/333694580_Structure_of_Micelles_of_Sodium_Dodecyl_Sulphate_in_Water_an_X-ray_and_Dynamic_Light_Scattering_Study
Hi Mitesh Gor , hope you were actually able to find the micelles. As pointed out the presence of larger species would overwhelm the signal and make small micelles "disappear" in the measurement. This may be overcome by filtration or centrifugation or sample preparation in general. An additional concern is that the Nano S90 is not as sensitive as the backscattering system, which means that it may require a larger sample concentration than different optical configuration.
https://www.materials-talks.com/blog/2016/01/12/how-do-dls-size-results-differ-with-angle/
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