Tuesday, April 6, 2010

Surfactants: How to interpret the names of surfactants

I know there's a lot of misunderstanding about surfactants - especially about SLS - so here's a way of figuring out what type of surfactant you have!

Sodium lauryl sulfate

Okay, the sodium part is the cationic or positively charged ion in this surfactant.
The lauryl part indicates which fatty acid was used to make the surfactant. In this case, it's a lauric acid (C12) fatty acid.
The sulfate part indicates it was made through the process of sulfonation, and the sulfate is the negatively charged ion in this surfactant.

Ammonium Laureth Sulfate (ALeS) or Sodium Laureth Sulfate (SLeS)

In this case, the ammonium part is the cationic or positively charged ion.
The laur- indicates it is derived from lauric acid (C12).
The -eth part indicates that it was derived from an ethoxylated fatty alcohol as opposed to directly from the lauric acid. (There's a step in there I'll go into when we get to the alkyl ether sulfates).
And the sulfate indicates it was made through the process of sulfonation. The sulfate is the negatively charged ion. (I'll get more into this when we get to the post...)

Sodium C14-16 Olefin Sulfonate
The sodium is the cationic or positively charged ion.
The C14-C16 indicates the type of fatty acid used in the surfactant (C14 - myristic, c16 - stearic).
The olefin indicates it is a straight chain organic molecule (click here if you are dying to learn more!) It is an unsaturated alkene, a straight chain with at least one double bond. (You might remember the whole unsaturated-double bond thing from the oils and butters.)
The sulfonate part indicates it was created through a process of sulfonation, but the sulfur is directly linked to a carbon molecule.

Decyl glucoside (non-ionic surfactant)
The decyl part indicates that it is derived from the fatty acid 1-decanol, a straight chain fatty alcohol with 10 carbons (hence the decyl - dec- means 10).
The glucoside part means that it is derived from glucose.

Not all surfactants follow these rules, but if you know the different between sodium lauryl sulfate and sodium laureth sulfate, then I'll be a happy girl!

Join me tomorrow for fun with carboxylates!

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