Monday, January 14, 2013

Facial scrubs: Creating a surfactant based scrub - rinsing off cleanly

Yep, that tight feeling you get after washing isn't about removing oils from your skin - although that can be an issue with repeated washings - but about the surfactant rinsing off cleanly! What has been shown to be an essential component of skin tightness is the film left on your skin after rinsing off the surfactants. The worst culprits for this are the alkyl sulfates (like sodium lauryl sulfate or SLS) and the alkyl benzene sulfonates (also known as the alkyl aryl sulfonates like linear alkylbenzene sulfonate, which are mostly used in household cleaning products). (From this post)

We can avoid this feeling in a few different ways...

1. By using surfactants that rinse off cleanly, meaning SLS is probably not an ingredient we wish to include in our facial cleansers.

2. By using lower concentrations of surfactants - no more than 50%, but preferably lower.

3. By adding cationic or non-ionic ingredients - cationic polymers like polyquat 7, honeyquat, or cationic guar gum or non-ionic ingredients like PEG-7 glyceryl cocoate or polysorbate 80 - which also increase mildness. We can include non-ionic water soluble esters - like water soluble shea butter, PEG-7 olivate, Cromollient SCE, or Caprol Micro Express - as emollients and mildness enhancers that will help our products rinse off more cleanly!

Now that we've chosen our surfactants and we've figured out a few ingredients we'd like to include, let's take a quick look at how pH affects our products before we create a sample recipe and add some physical and chemical exfoliants.

2 comments:

Robert said...

This is a very helpful post as it gives an excellent summary of a number of possible conditioning agents to enhance the after feel of a facial cleanser/shower gel/shampoo. I expect it took many years of study and experimentation to come up with this.

To show how many possibilities exist, one supplier (Ashland) offers around 12 different choices of cationic guar alone, all with the INCI name guar hydroxypropyltrimonium chloride. See:

Cationic Guar choices

Each cationic guar has somewhat different properties with respect to moisturizing, volumizing, conditioning, skin feel, suitability in clear systems, suitability in opaque system, etc. It takes a lot of experimentation and a clear idea of what you are trying to achieve to choose which works the best for a particular purpose.

Anonymous said...

Yep, that tight feeling you get after washing isn't about removing oils from your skin - although that can be an issue with repeated washings - but about the surfactant rinsing off cleanly! What has been shown to be an essential component of skin tightness is the film left on your skin after rinsing off the surfactants.

Interesting! I never heard before, where it's not about the surfactants at all, but the film.