Wednesday, May 29, 2013

Using decyl glucoside in our products: pH and thickening

As I mentioned yesterday, decyl glucoside has two main drawbacks - a high pH (as high as 11.5) and difficulty thickening. Let's take a look at those issues!

The pH for decyl glucoside is alkaline, and can go quite high. If you want to use this as your main surfactant, you'll have to work to get that pH down below 6.0. In this recipe, the pH was too high thanks to both decyl glucoside and disodium cocoamphodiacetate, but I used my trusty pH meter to measure it and citric acid to bring it down to a reasonable level. (You can reduce pH through the use of various acids, but citric acid is the cheapest and easiest to find.) In this recipe for a foaming facial cleanser, I had a good pH of 6.05, but I only used 5%.

If you want to use decyl glucoside in any serious amounts - I'd say 10% or more - I would invest in a pH measuring device. I have used the strips in the past and I didn't find they worked well for me, but you can give them a try if you wish.

pH is a major issue, and you really must keep this in mind when making any product. If you make something out of the right pH range, you can cause problems with your hair or skin. You can't just throw 20% decyl glucoside into a recipe and assume the pH will be right as the odds are good you've just thrown something that was in the right range - 5.0 to 6.0 - into the alkaline range - over 8.

Related posts:
Weekend Wonderings: Reducing pH
Chemistry Thursday: Let's take a look at pH
Chemistry Thursday: How to measure pH?
Weekend Wonderings: The importance of pH in shampoo (scroll down a bit)

The other issue is that we can't thicken decyl glucoside easily, which is one of the reasons I tend to use it in foaming bottle products. There are three main ways we thicken our products: by increasing the concentration of the surfactants, by increasing micelle size, and by creating gels.

Increasing the concentration of the surfactants isn't just about adding more surfactants; it's about fooling the system into thinking there are more surfactants. We don't want to add more decyl glucoside because of the high pH, so can we fool it? We can, and we can do this by adding salts or electrolytes. But here's the problem - decyl glucoside doesn't care about the salt curve or electrolytes, so it won't work. It might work for the other surfactants you're using, but it seems like people want to use it on its own, so salt isn't an option.

Can we increase the micelle size of decyl glucoside? Sure, we can add fatty ingredients like Crothix or glycol distearate, but these things aren't as effective as they could be and you could be using huge amounts to get some minor thickening.

I tried it with a shampoo I designed to be for oily hair, and I had to add so much Crothix to the product that it felt slimy! Your experience may vary!

Can we create a gel? Yep! That's the recommended way to thicken a product with loads of decyl glucoside. Try using xanthan gum at the suggested usage rate of 0.1% to 0.3%, Amaze XT at up to 2%, or other gel making things like carbomers or guar gum at the suggested usage rates. Make sure you aren't using things that will break the gel. This is a fine art, and I suggest reading all you can before you try it, then keep amazing notes!

Seriously, read all you can, because it's not as simple as making a gum and being pleased with it. It can morph over time, come out of solution, create a goo on the bottom, and so on. Take a look at this post at the Chemist Corner forum for some ideas. Or check out this document on the topic. And remember to balance the pH before you start the thickening process! Or do what I do and use a foamer bottle for your product and avoid all that thickening stuff! :-) 

Now that you have a few ideas of how to use decyl glucoside, let's take a look at how we can use it in our products! Join me Friday for a few ideas on how to substitute it for other surfactants before we use it in a few products we'll formulate from scratch.


Molly said...

I'm just about to start playing with surfactants so I'm loving these posts!

Thanks for all the great info (as always!)


LeKenda said...

Interesting. I have still as of yet the mastering of surfactant blends. My major problem is thickening with a more natural substance like guar gum. Thanks for the link to read more.

My current question: what do you think about making a shampoo for a foamer bottle. We are so use to something more substantial but what about a foamy cleanser for our hair?

Ruben said...

I don't understand why decyl glucoside has a high pH, considering that is is non-ionic compound. Where the high pH comes from? Is the product adjusted to pH 11 or so on purpose by the manufacturer?
Thanks a lot

Robert said...

One prototype formulation from the manufacturer of decyl glucoside uses a special grade of xanthan gum (Keltrol CG –SFT) as a thickener. The normal grade of xanthan gum is good for creams and lotions.The SFT grade is better suited for surfactant systems. But, I cannot find the SFT grade available from any supplier.

A second prototype formulation uses acrylate copolymer as the thickener. This thickener is sold under the tradename Carbomer Aqua SF1. This specific ingredient also does not seem to be available.

Within your post, the link ‘check out this document on the topic’ mentions the ingredient Antil Soft SC. This ingredient is a very efficient thickener (and Ecocert-certified) for sulfate-free systems but is also not available.

It makes it very difficult and frustrating when the best ingredients for thickening decyl glucoside are not available from the regular suppliers.

WS said...

I use "MaizeThix" modified cornstarch, 5-6% to thicken a decyl glucoside shampoo and it works splendidly. I add citric acid before adding the surfactant to the gel. The final result is neither clear nor cloudy - more translucent.

Anonymous said...

When using guar gum or xanthan gum I find it helpful to wet out the powder with IPA (rubbing alcohol). Make sure the powder is completely wet then add to product and mix under shear force. IPA makes the gum dissolve better because when the gum hits the water straight it can gel and glob on contact, having the gum covered with the non polar IPA allows it to ease into the system.

Anonymous said...

A domestic manufacturer of xanthan gum is CP Kelco, they may have a source that can sell by less than the 50 pound bag it comes in. It is expensive stuff though, even at a 50 pound bag it can be over $10 a pound.

Susan Barclay-Nichols said...

Please put your name on your posts or I will delete them. And I hate to do that because this is very helpful, but I can't make exceptions to a request I've made repeatedly and obviously! said...

Actually there are pre-neutralized version of decyl glucoside available on the market, PH is around 7.

Good point on thickening, while the lauryl glucoside has a much higher viscosity if you like to use it.

Mandy said...

Does anyone know if there is a powdered form of decyl glucoside? Or, is there another powdered surfactant that would work well as a laundry detergent? Thank you so much!

Susan Barclay-Nichols said...

Hi Mandy. I've used your question in Saturday's Weekend Wonderings. I wouldn't want to make my own detergent as you could run into problems with your appliances!

Mandy said...

Thanks so much!

Jonica said...

I have thickened it with Xanthan with decent results and I purchased it at "ingredients to die for"

Aya ghussain said...

hello,thank you for the informations,i have a question please i wnat ot make a shampoo of my own where decyl glucoside is the base ,what kidn of Problems that may occur beside the high ph that can be reduced by citric acid for example please?thank you