Tuesday, December 14, 2010

Surfactants: Disodium cocoamphodiacetate

I've bought a new surfactant to play with over my two week holiday at Christmas! It's disodium cocoamphodiacetate (aka Amphosol 2C by Stepan)!

Disodium cocoamphodiacetate is a mild amphoteric surfactant, much like cocamidopropyl betaine. The "ampho" part in the name indicates it's amphoteric, meaning it carries a different charge in different pH levels. If it's acidic (below 6), it behaves as a cationic surfactant that will be substantive to our hair and skin, offering moisturizing and conditioning properties. If it's alkaline (above 8), it behaves as an anionic surfactant with good foaming and detergency properties. (Click on the link for cocamidopropyl betaine if you want more information on the chemistry!)

It's generally used as a secondary surfactant to boost foam and viscosity, and it can be used as a very gentle cleanser for sensitive skin, babies, and facial products. It has a pH of 8.5 to 9.5 (which is higher than cocamidopropyl betaine), so I'll have to make sure I alter the pH if I'm using a lot of in my products with citric acid (just a titch). It comes as about 38% active in our products, and the suggested usage rate is up to 50%!

You will likely see this surfactant used as a primary surfactant for baby products as it's non-irritating to eyes at up to 5% and because it's very mild. And you'll likely see it combined with decyl glucoside in a lot of natural products or cleansers for sensitive skin as this combination creates a very gentle cleanser that won't strip a ton of oil off your skin! If you want to use this combination, you will have to test the pH and alter it slightly with citric acid.

If you want to use it as a secondary surfactant, it works with any combination of anionic or non-ionic surfactants, much like cocamidopropyl betaine. It will increase the mildness of your surfactant blend and it will increase the viscosity of your product. It does have a slightly yellow tinge, so if you want a completely crystal clear product with no colour, it might not work for those applications. But really, when you have a very gentle cleanser that offers moisturizing and conditioning, increases the mildness and viscosity, and doesn't strip the oils from our hair and skin, is a hint of yellow really going to make that a big a difference?

Click here for the data sheet from Stepan.

Join me tomorrow for fun formulating with this new surfactant!


Aesthete said...

OMG, this is one of my favorites! looking forward to your post.

Tara said...

Hi Susan. I am interested in formulating a baby wash/shampoo, both for my baby and for removing eye make up. The facial cleanser I've made for myself stings my eyes terribly :(

Susan Barclay-Nichols said...

Hi Tara! What are you using in the recipe (post it here or e-mail me) and I can help you modify it a bit.

Now that I have my pH meter, I can use some of these more alkaline surfactants!

Tara said...

Hi Susan. I went to look for my recipe, but I am afraid it was undetailed (very unorganized, I know). So it was *something* like this:

40% gentle surfactant (don't remember what I used)
10% coco betaine
10% aloe or hydrosol
2% Na lactate or glycerin
2% salicylic acid
2% Cromoist
2% panthenol
0.5% each honeysuckle and cucumber exract
can't remember which preservative, but I am assuming Cosmocil CQ would be most gentle for the eyes
up to 2% Crothix
qs with water

So since I am after a "tear free" mix, I am assuming salicylic acid, Na lactate and honeysuckle extract might not be the best choices. I would probably use chamomile as my choice of hydrosol. You say disodium cocoamphodiacteate is non-irritating to the eyes at below 5%, so what would you suggest for the rest of the 35% of the surfactants?

Thanks Susan!

Unknown said...

I'm altering a homemade shampoo recipe by replacing the detergent with this, but was wondering in what common form could I buy this in?


Unknown said...



Susan Barclay-Nichols said...

I'm really not sure why you'd want to make that recipe from Instructables when there are so many good shampoo recipes on this blog, in various forums, and in our suppliers' formularies. I mean no offence to the writer of the Instructables recipe, but this isn't a shampoo - it's a watered down soap with an alkaline pH and no preservative. I've looked at other ideas she presents and I really wouldn't recommend any of the recipes as they are unpreserved and not the right pH for your hair.

I'm not really sure what you're asking. The ingredient is called disodium cocoamphodiacetate, and you can look for that INCI name at your local supplier. But you'll want to alter the pH if this is the only surfactant you're using in a shampoo.

Susan Barclay-Nichols said...

I spent a bit more time on that Instructables page. Please do not try that recipe. It is not going to feel nice on your hair, it isn't preserved, and she is making all kinds of claims about the shampoo that shouldn't be made. I cannot stress enough how concerned I am that this recipe is out there on the 'net for anyone to try. This is not a good recipe for myriad reasons. Please find one from the Herbarie or the Dish forum or this blog or anywhere else. Please don't make this shreds of castille soap in water recipe!

Rhonda said...

Hi, Susan--
Would sodium cocoamphoacetate be a replacement for disodium cocoamphodiacetate as far as conditioning feel and foamining ability?

Anna said...

Hi Susan,

I just read the recipe that you wrote a comment about (http://www.instructables.com/id/Homemade-Shampoo/) and I think it´s great that she is creating her own shampoo! If she is having fun and is also inspiring others to have fun, than what´s the harm?

Ok, so in this case there might be some harm since she isn´t using a preservative but otherwise, I say good for her!

Susan Barclay-Nichols said...

Hi Anna. There's a lot of harm in making an alkaline shampoo that doesn't have preservatives. It doesn't matter whether she is having fun. She is encouraging others to make a harmful product. Shouldn't I woeak out about that? Would you be happy with her product? Why are you defending that recipe? I'm honestly curious!

Anna said...

Hi Susan! I absolutely agree, you shouldn´t make a shampoo without a preservative. I just felt you went a little hard on her, when it comes to the feeling on the hair and about making claims about the shampoo. I have made some TERRIBLE shampoos that have made my hair feel dry and brittle, but I have had fun creating them nonetheless. And I hope that people won´t judge me for creating and sharing just the recipes that I want, even if they aren´t very well formulated.

And just to be clear, I absolutely think that a shampoo has to contain a preservative.

Susan Barclay-Nichols said...

Hi Anna. Would you prefer that I say nothing and let people make a recipe they'll hate? If you bought all the supplies for that shampoo and created something you hated, would you be pleased? Or would you prefer that someone had warned you? Would you want to make something again if the first thing you have made didn't feel great?

I was on a forum and someone posted that they "sell lip balm now" with this recipe - lime juice, sugar, and Vaseline. I wrote that I thought this was a dangerous recipe, and was told I wasn't being very nice. I thought preventing others from making something dangerous was being nice, but I guess it's more important to worry about someone's feelings in being corrected than it is to put out correct and safe information.

Where did I judge her personally, calling her names or being cruel? I have no feelings about this person as a human being. How would you prefer I leave feedback about a recipe of this nature? I'm not judging her. I'm judging the recipe. (If you want to find my comment and post it here, that's fine with me...) If you put something on the 'net, expect there will be comments about it. If you can be open to listening to those comments, you'll learn how to create better and better products! That's how we learn!

I would hope that if I wrote a recipe someone didn't like, they would comment. In fact, I'd be upset to find out that a recipe I wrote didn't work and no one said anything! It's the users' responsibility to give feedback!

I'm going to be honest - I'm still not sure why you're being an apologist for this recipe? Did you try it and love it? Are you the person who wrote it? Do you know the person who wrote it? I'm also not sure why we're discussing this in a post on disodium cococamphodiacetate?

Anna said...

Hi Susan, I am discussing it here since you wrote the comment about the recipe here. I could send you an e-mail instead if that is what you prefer?

No, I absolutely think you can warn people about badly formulated recipes, just as I can comment that to me, the fun of creating a product is more important than the final result.

Yes, I would probably be pleased even if I created something that I hated, and I would also give it another go. Because I think it´s fun to experiment!

I would also agree that warning others about dangerous recipes is a very good thing! But to me there is a different about warning people about a recipe being dangerous and about a recipe being safe, but poorly formulated.

No, I don´t know the person who wrote it. I am actually one of your keen readers.

But I like what you write about how to confront you when we don´t agree with you, to do so in a friendly and supportive way!

I think one of the main reasons we are having this discussion might be because we have different opinions about why we make personal care products or cosmetics. I think that you are focused on making a good final product (and i totally get that!), while to me, the experimental process is the most important part. To me the final result isn´t very important.

I am really not defending this recipe since I think you have to use a preservative. I think that I am actually just defending the right to create and share badly formulated recipes.

Finally I just want to add that since I am not from an english-speaking country I just hope that I am not coming of as rude because of language difficulties.

Kate said...

Personally for me, I would nothing more but make good shampoo from the first try. My goal is to make something what is great for my hair. I spend too much time and ingredients to make the best shampoo (still trying), It's not fun for me to try new formular that doesn't work, again. If professional says that formula on that website is harmful for my hair I don't want to waste my time and appreciate when someone warn me ahead of time about it. I want formular that works! In the end of all, most of us here want to learn how to succeed, not have fun wasting ingredients and time.
I'm not from english-speaking counry either and hope you got my point.