Creating a daily use shampoo, longqtruong asks, You have dimethicone in your daily shampoo formula which is not water soluble. Do we need a solubilizer or emulsion system to make this work?
The short answer is probably not. The longer answer is as follows...
You're right: The forms of dimethicone I've been using in my products aren't water soluble - there are some like PEG-8 dimethicone or amodimethicone which are - but I'm including them in my shampoo without an emulsifier or solubilizer. This is because surfactants - the foamy, bubbly, lathery kind - are surfactants or surface active agents that have some emulsifying power in them.
I've been playing with water soluble dimethicones and I'm very excited about them! There'll be lots more about them shortly...
The bubbly surfactants we use work the same way. They surround the sebum on our scalp or body and put it in a little micelle to be washed away. (Check out this post on how shampoo works to learn more.)
They can do the same thing with an oil soluble ingredient like dimethicone or olive oil, for example. But some surfactants are better as this than others. If you look at the surfactant comparison chart, you'll see that C14-16 olefin sulfonate is a good emulsifier, while disodium laureth sulfosuccinate (DLS) isn't.
So the longer answer is that if you're using a surfactant that acts as a good emulsifier or solubilizer, like C14-16 olefin sulfonate, you don't need to add anything else if you want to use 2% dimethicone or 3% carrier oil, for intance. If you're using a surfactant that doesn't work well, then you might want to use a solubilizer like PEG-40 hydrogenated castor oil, polysorbate 80, or caprylyl/capryl glucoside to the mix, keeping in mind that these ingredients can suppress foam and lather.
Better yet, if you want to add some moisturizing to the mix, consider using a water soluble dimethicone, like those I mentioned above, or a water soluble oil, like Olivem 300 (INCI: Olive oil PEG-7 esters)* so you don't have to add a solubilizer to the mix.
glycol distearate, which works as an emollient, thickener, and pearlizer, like you see in this recipe or in this recipe.
*You can find Olivem 300 at Lotioncrafter (USA) or Windy Point Soap (Canada). I provide this information as a help to you, my lovely reader. I receive nothing for sharing this information and these aren't affiliate links. Just want you to know that...
Adding oils to a body wash
Modifying a body wash with oils
Formulating for dry skin: Basic recipe with oils