Thank you very much Stéphane!!!!
I had read very quickly n-hexane in the abstract thinking in inverse micelles, but I believe that it will help me. Merciiii!!!!!
In fact, I am afraid that there is no cmc for Span surfactants in water: they are very hydrophobic and their HLB is quite low, but I may be wrong!
yes, it has been imposible to find them. Thank you for your comments!!!!!
Clearly, I had never worked with these surfactants (they are absolutely insoluble!!!)
I wanted to test several micellar solutions (in water) of spans (and other surfactants) vs. liposomes, so I was looking for thier cmc's
Dear Mercedes,
cloud point of the Span type surfactants is much below room temperature. This means there will be a coexistence of a concentrated surfactant phase and a very dilute aqueous surfactant solution. The concentrated surfactant phase will be of course able to solubilize different substances, as in use for cloud point extraction.
If I understand correctly you want to study solubilization efficiency? What are the target substances?
yes, I wanted to compare solubilisation efficiency of different surfactants commonly used in cosmetic formulations vs. liposomes, thus I chose some span surfactants (among others). I had never worked with them and unknown how they behaved in aqueous dispersion.
Mercedes
I hope, that the concentrations of CMC about which you asked, will be useful for you.
Previously, I missed the question, and account for ResearchGATE have only one and a half month.
I had not noticed this question early, and still account on ResearchGate I have less than two months.
Due to ethoxylation the Tweens are water soluble opposite to the oil soluble Spans. Thats why you find literature values of cmc for the Tweens but not for the Spans.
Dear Andrzej, thanks for your kindness and your information. As Titus says, Spans are ethoxilated surfactants like Tweens, but they are not dispersible in water.
Thanks again.
To be exact Tweens are ethoxylated Spans. Spans are the esters of sorbitan without ethoxylation.
My question is the same Ms. mercedes. As your view, is it possible to find the CMC span 80 in cylcohexane? I found two papers dealt with this by interfacial tension and conductivity measurement. :( anybody can help me?
these surfactants are no able to form micelles alone in water dispersion (they are not water dispersible)
Dear Ms. Mercedes, I know that but I am going to use Span 80 for inverse emulsion of polyacrylamide, which concentration of span 80 should be considered to make micelle?
alone, span 80 + water as other water dispersible surfactants.
sorry, but I don't know the concetration of spam
Dear Yousef,
did not worked with Span in cyclohexane, however, as a start I would Google it. You will find some related results searching for 'CMC span 80 in cylcohexane'. What should interest you more is solubilization of water in the reverse micelles.
I know that it's too late but this might help others if they have the same question
http://ac.els-cdn.com/S0021979700968103/1-s2.0-S0021979700968103-main.pdf?_tid=808bbf62-de47-11e6-ae88-00000aab0f26&acdnat=1484831116_1a89684566b767b4b40b05bdeac4ec38
abstract says
'At the water–n-hexane interface, differences in CMCs were small'
this shows that they misinterprete breakpoint in interfacial tension as synonym for cmc.
The interface as such has no cmc. Micelle formation is what happens in the bulk. Breakpoint for surface tension mostly coincides with micelle formation in aqueous phase but will also occur when solubility limit is reached, i.e. below the Krafft point temperature. For measurement in water-hexane system the breakpoint concentration will depend on degree of partition between two phases, phase ratio and on how far or close partition equilibrium is reached.
hi, I am looking for CMC for span 80 in cyclohexane for inverse suspension polymerization. can anyone help me?
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