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Why are non-polar hydrocarbons killing my emulsion viscosity?
I am some kind of freak when it comes to emollients. I have a room full of them. I love experimenting with them neat on the skin…seeing how they absorb, and observing after-feel… 30 min to two hours later.
Twice in the last year… Hemisqualane ( C13-15 Alkane) coaxed me into inserting it into an existing, well tested formula…where when it was added at 2%, it totally blew the viscosity!
What did @Pharma not teach me…that I am overlooking? Is there some simple hack to keep from losing major viscosity? I would love to use this ingredient, but not with this much formula disruption…. I can go back into that room..and pull another one off the shelf….but I am stubborn and intrigued.
Aloha.
If you want to link an article, or good read….I am always up for further education.
FYI: The favorites in my collection are: Ethylhexyl Isononanoate, gotta love those branched chain esters, and Dicaprylyl Carbonate. As most of you know…I hate a greasy/oily feel.
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9 Replies
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It depends on what’s in your formula, but increasing oil content can modify micelles which can change viscosity.
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I always sub out 2% of the emollient package, to introduce the 2% hydrocarbon. So oil phase ratios stay the same.
Are you saying…this is an odd situation?
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Not all oils are the same and they can affect the micelle structure differently even if the ratio is the same.
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Sorry, I was replaying to a wrong topic.
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Your regular emulsion has a high viscosity because you got a complex micellar arrangement (worm-like or rods, that can even be entangled). When you introduce hydrocarbons, they go to the core of your micelles and cause a transition from worm-like (viscous) to spherical (non viscous). Just a question, are you emulsifying the hydrocarbon with the whole oil phase? Or adding it after?
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I am just adding it to the lipid phase in an O/W emulsion.
I have learned over the years…that certain ingredients prefer to work with certain emulsifiers.
This particular emulsion was M 202 + GSC+GMS+Sucrose Stearate, plus typical builders.
(SS in the water phase, so it is hydrated and ready to work…upon combining.)
Use of fatty alcohols…assumed.
I had…subbed all the steric hindrance aspects over to .5% SeaBalance…in an experiment, but don’t believe this was fundamental in the viscosity loss. I had a similar result a year ago, before SeaBalance was even a twinkle in my eye.
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@ketchito is there a hack you implement, if you are using hydrocarbons in a formula?
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I’d try to pair emulsifiers with a bit more similar structure so lamellae has better packing (the sucrose in your sucrose stearate might have a negative steric effect).
By the way, what is SS? ???? I’d also increase viscosity of your water phase (HEC might work, but I prefer something with emulsifying properties, like Structure XL….or even Natrosol Plus 330).
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SS = Sucrose stearate / sucrose esters.
I guess I will work around the hydrocarbon, as I have many alternatives, and prefer my formulas to serve as frameworks for other formulas, where I can just drop about anything in. If I tailor it to the hydrocarbon, that means I would have to reformulate…on the next similar formula….and dang if I’m not lazy. 🙂
My initial thought is, I will just bump the Lauryl Laurate. What isn’t better, with more of that?
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