Greetings,
I am trying to figure out the biggest differences between CMC and CVC and perhaps somebody can help me. Before that, I am doing turbidity analysis in my research in which I use UV-Vis and Fluorescence as my equipment to determine CMC and CVC.
But, i just wondering and would like to know :
1) How can I know which one is CMC and CVC results?
2) Is it all surfactant that give CMC result will give CVC result?
3) What is proper methods or equipments to determine CMC and CVC?
Thank you for those who can help me :)
Both CMC and CVC in aq. solutions can be determined by any conventional method described e.g. in Surfactants and Interfacial Phenomena of Milton Rosen. Generally, vesicles are larger than micelles. Vesicles are hollow inside, often multilayered that can be seen by the (cryo)TEM imaging.
you can differentiate between them using TEM. Vesicles are larger in size.
Hi Nurul,
Surfactant systems can be characterised by dynamic light scattering which will report micellar size. Additionally, measurements over a range of different concentrations using DLS can reveal CMC.
The following application note may be of interest.
http://www.malvern.com/en/support/resource-center/application-notes/AN101104SurfactantMicelleCharacterization.aspx
DLS can also be used to measure viscoelastic properties/microrheology which is a area of interest for micellar systems.
cmc only exists above Krafft temperature, and I assume is much more defined than process of vesicle formation, which often needs assistance of e.g. sonication. Not sure whether vesicles are thermodynamically stable, as is the case for micelles, or only metastable entities. Vesicles can only be formed when ratio between headgroup area and cross section of hydrophobic chain is close to 1.
https://www.researchgate.net/publication/266148923_Vesicle_formations_at_critical_vesicle_concentration_in_a_polyoxyethylene_type_nonionic_surfactant_systemSee
maybe one of useful reference
Article Vesicle formations at critical vesicle concentration in a po...
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