Saturday, April 17, 2010

Surfactants: Sulfoacetates

We generally find the sulfoacetates as sodium lauryl sulfoacetate (SLSa), which is found in powder or flake form. It is created by the esterification of sulfoacetic acid. It is milder than than the ethoxylated alcohol sulfates (like SLeS) and stable in hard water.

The flakes or white powder have about 65% active SLSa with a pH of about 6.3, which is perfect for our skin and hair products. There is moderate skin irritation at 70%, but we don't use levels that high, so consider this a mild cleanser.

SLSa is an excellent foaming, bubbling, and lathering surfactant. It offers great cleaning and detergent properties.

I use this product in foaming bath bombs and in shampoo bars as the white powder, and in a ton of other products like facial cleansers, body wash, and shampoo as LSB (which is SLSa and disodium laureth sulfosuccinate). It's a great inclusion in foaming bath salts as well.

Some people find SLSa makes their hair feel crunchy when used in a shampoo bar. If you're one of these people, consider using extra moisturizers and conditioning agents in a shampoo bar to eliminate this sensation. Or substitute something like Bioterge AS-90 (C14-16 olefin sulfonate, powdered) for SLSa, which offers great foam and cleansing, but the bubbles aren't as great as SLSa.

When you're using this product, make sure you wear a mask. It is composed of fine particles that get into your nose and mouth, which is seriously unpleasant!

Click here for a data sheet on Lanthanol, Stepan's version of this product.

Join me tomorrow for fun with sarcosinates!


Anonymous said...

Where does the sulfoacetic acid come from?

Claudia said...

Hello Susan, I read about your posts on BSB and coco betaine. I supoose they are the same thing, aren't they?

I make my own CP soaps, hair conditioner and lotion/cream. I use CP soaps for my hair but after a couple of washes I feel it has become too dry. It's okay after applying hair conditioner.

After reading your last post I am keen to try to make my own shampoo. Is making shampoo the same as emulsifying water and oil? Or it doesn't have oil component in shampoo? Is PEG 150 distearate an emulsifyer? Is it compulsory in shampoo making? If so, is it possible to add oil (as conditioner) in shampoo, acts as a 2 in 1 kinda thing? I think I read somewhere that you can't use BTMS in shampoo. I might be asking silly questions. Keen to hear your advice.

Susan Barclay-Nichols said...

I have no idea where the sulfoacetic acid for SLSa comes from specifically, but I'm guessing a chemical reaction between sulfur and acetic acid.

Hi Claudia. BSB and coco betaine are both surfactants, but that's really where the resemblance ends. BSB is an anionic blend of surfactants and thickeners, while coco betaine is a single amphoteric surfactant.

I started the series of posts on surfactants on April 6th - here's the first post.

Making shampoo is nothing like emulsifying oil and water - I wouldn't include an oil component in a shampoo as it will reduce the lather and really doesn't serve a purpose. (Save the oils for the decadent conditioner!) PEG-150 distearate is like Crothix; it's a thickener for the surfactants. No, it's not compulsory, but you will likely want to use a thickener in a shampoo (more on thickeners starting the 23rd). I wouldn't use oil as a conditioner for a 2 in 1 - you're better off with a cationic polymer or dimethicone - and you can't use BTMS in a shampoo as it will precipitate out and leave a horrible mess (I've tried it; I know). You can, however, use it in a solid shampoo bar with good success; I use CR because it feels pretty much the same, but adding a conditioner is a good idea.

My initial shampoo post is here - shampoo post - or you can do a search for shampoos to find various posts on this topic on this blog. Here's my basic download on surfactants (including shampoo), that might interest you.

I'm planning to go into great detail about formulating shampoo products after the facial care products - probably around the 2nd week of May.

Ai Shiang said...
This comment has been removed by the author.
Claudia said...

Thanks for the explanation, Susan. I always thought that making shampoo had to start from using potassium hydroxide.

I'll keep on reading.

Tara said...

Hey Susan. I am wanting to make a bubble bath, hopefully with Lathanol (SLSa). I know you mainly use this for powdered bubble baths, but can it be incorporated into liquid bubble baths too? I wouldn't know how to do this (melt it? dissolve it?). I also have coco betaine and Bio-Terge AS-40 to round out the bubble bath blend, but I want to use up some of my Lathanol without my son inhaling it when I add it to his bath ;-)

Susan Barclay-Nichols said...

Hi Tara. I've tried to use SLSa in liquid bubble baths before, and it's tricky. I think my last one was 15% and it was a bit difficult to get out of the bottle. I'd say try it at 5% of your surfactant amount, and see how it works, then up to 10% of your surfactant amount and see how you like it. It can harden up quite a bit, so I'd suggest increasing your glycerin amount (which will behave as a plasticizer) to at least 5% or so. It's a great addition to a bubble bath as SLSa is a fantastic foamer and bubbler, so give it a try!

Tara said...

Hey thanks Susan. I will definitely try it! So do you have to melt it in water, or will it "dissolve" in my other surfactants?

Susan Barclay-Nichols said...

Hi Tara! You can melt it in water, but that can cause bubbles, so I'd melt it in the surfactants the way you'd do with SCI.

Tara said...

Forgive my ignorance, Susan. I have never used SCI (yet), so I appreciate your instruction :)

Much thanks!

Tara said...

Hi Susan. It has taken me until now to formulate the liquid bubble bath with SLSa. I really like it! I used 10% SLSa with 25% cocobetaine and 25% Bioterge AS-40. I also included 5% glycerin like you recommended. It took over night to solubilize/dissolve the SLSa, but the next morning it was wonderfully clear and not TOO thick. And the bubbles are much closer to commercial bubble baths than they are with just Bioterge or LSB. Thanks so much for your help!

Anonymous said...


where can i find SLSa in london?I have been struggling

Crombie said...

Have you ever tried using SLSA in soap? I'm thinking of experimenting and using foaming bath salts in HP salt bars (which are 50% salt) - added at end of cook after saponification. Do you think this would work?

Susan Barclay-Nichols said...

Hi Crombie! No, I don't make soap, so I haven't tried it. Keep in mind it has a pH of 6.3, so it's much lower than that of soap. I don't know what that will do to the process. Let us know if you try it!

Lana said...

Hello Susan,
First of all,
Thank you for this wonderful blog. I read it often and finally decided to try making my own solid shampoo bars....but...Bummer! Whenever I add Sodium Lauryl Sulfoacetate (SLSA), my bars get that chemical stench (not sure why it's never mentioned anywhere online) and I can't get rid of it! Even the addition of 2.5% Lavender EO doesn't help....would you know why this is happening and what to do abt it? Thanks:)

Lana said...

Hello Susan! First of all, thank you for this blog. It is very interesting and helpful:) I finally have gotten the ingredients for making the shampoo bars (Yey!) but, oh bummer, when I add SLSA, they start to stink of chemicals (slsa smell) and I cannot get rid of it even by adding 2.5% Lavender EO (the chemical smell still punches through)....what shall I do? Thank you:)