Sunday, January 13, 2013

Facial scrubs: Creating a surfactant based scrub - introduction and choosing our surfactants

Why choose a surfactant based scrub over an oil based or emulsified one? A few reasons! Some of us can't tolerate loads of oils, and a surfactant based scrub is less likely to be comedogenic or acnegenic. Secondly, you clean while you exfoliate, so it does two jobs in one! (Some would argue that the oils clean your skin, some of us won't feel that way!) And third? You can add those wonderful chemical exfoliants that we can't in anhydrous (non-water containing) products, as well as the physical exfoliants we've come to love! (Click here for part one and part two of the physical exfoliants!)

The first thing we should do is create a surfactant base our skin loves, then we can add the exfoliants. If you already have a base you love, then add the exfoliants as you wish! 

What is the goal of this surfactant based scrub? We want something that gently cleans our skin, something with a decent viscosity to keep the scrubbie bits suspended, and something that washes off cleanly so our skin doesn't feel tight or dry. We want gentle exfoliation to remove those dead skin cells and we want to make sure the product is in the right pH range. 

The first step is to find the right combination of surfactants to gently cleanse your skin according to your skin type. 

These are the sections of the blog to which I will refer regularly as we create this product. If you aren't familiar with these sections, I encourage you to click on the links as it would take weeks to get to the point if I had to review all of this information and I'm pretty long winded as it is!

You'll want to consider a few things when looking for surfactants for a facial product. Consider the skin type for which you are formulating and what surfactants are available at a supplier near you. I always choose at least one anionic surfactant (negatively charged) and one amphoteric surfactant (could be negative, could be positive) for a product. For the anionic ingredient, we have tons of choices. For the amphoteric surfactant, you'll want to choose between cocamidopropyl betaine and disodium cocoamphodiacetate. (More about these surfactants later in the post!) 

Click here for more information on charges of our ingredients. The quick summary is that our skin and hair are negatively charged, so we use negatively charged ingredients - anionic surfactants - to clean our skin and hair. 

We're planning to create a gentle to mild product, so we'll choose gentle to mild surfacants - which most of them are! - but there are surfactants that work better for different skin types. For my oily skin, I'd suggest C14-16 olefin sulfonate (Bioterge AS-40 or AS-90 in powder form) or disodium laureth sulfosuccinate (DLS mild). For dry skin, I'd suggest sodium methyl cocoyl taurate (SMC taurate) or sodium methyl oleoyl taurate (SMO taurate) or polyglucoside/lactylate blend. (It leaves behind a really moisturized feel, too moisturized for my oily skin!) There are some surfactants that work with all skin types like SCI or ACI (sodium or ammonium cocoyl isethionate), which leave behind a lovely conditioned feel, or sodium laureth sulfate (SLeS), which is mild and cleans nicely. 

If you have dry skin, I encourage you to click on these posts as I've covered most of the information you'll want there...

For the dry skin version, I think I'll work with SMC/SMO taurate and cocamidopropyl betaine. 
For the oily skin version, I think I'll work with DLS mild and cocamidopropyl betaine. 
For the normal skin version, I think I'll work with ACI and cocamidopropyl betaine. 
You can choose the surfactants you like and play along, even if you can't access these. There might be differences in how thick your product is compared to mine, but the cleansing and scrubbing properties will be quite similar! 

I'm often asked about decyl glucoside, which is a non-ionic or neutrally charged surfactant that is considered to be a greener surfactant. I know it's really popular these days, but the pH can be really high and we have to add some acidic ingredients to get the pH down to a good level for our skin, between 4 and 6.5, depending upon the ingredients and your skin type. (Having said that, Voyageur Soap & Candle lists their product as having a pH of 3 to 5, very acidic!) It's hard to do that without a pH meter, and I assume very few of you will have those. you can purchase pH strips, but I find they don't tend to work well for me, showing everything at around 6. Perhaps everything is around 6, but I don't feel comfortable making those assumptions. 

As a note, you don't need to know all of this to use the recipe we'll eventually create, but knowing our ingredients and what they bring to the mix is the first step to modifying products to create things you love and to be able to create products from scratch! 

Join me tomorrow as we take a look at the idea of having our product wash off cleanly! 

Related posts: 

5 comments:

Marjo said...

I cannot wait on tomorrows post! Trying to make my own version of a great cleanser by Suki with sugar and lovely foam i found it did not foam enough so the surfactant cleanser post of today and tomorrow are closely watched by me :)

Michele Clarke said...

This is what I need! I can't wait. Just need some surfactants. Can you use castile soap?

Mychelle said...

I'm really enjoying the scrub series! It's a great demonstration of how well you understand your ingredients and, how we can make small changes for big differences if we are armed with that knowledge. I'm so trying the cream cleanser scrub you linked on Sat. How did I miss that?! Thanks (again) Susan! :)

Valerie Jaquith said...

Hi Susan, I have the same question as Michele, can you comment on using liquid castile soap? Thanks!

Susan Barclay-Nichols said...

Hi Valerie. Sure, why not? I've written a post about the topic as today's Weekend Wonderings.