Thursday, September 9, 2010

Chemistry: Solubilizers, dispersers, and emulsifiers

What's the difference if an ingredient says it is soluble or dispersible?

When something is soluble, it means it will dissolve in the solvent and becomes part of a homogeneous solution. Think of it like salt dissolving in water. If you've dissolved it correctly, you can't see the flecks of salt floating in the water. (The salt is the solute and the water is the solvent.) So if something is a solubilizer, it will dissolve the solute into the solvent and you'll get one homogeneous creation. There is a limit to how much solute can be dissolved in the solvent before a precipitate occurs (the precipitate is the stuff that sinks to the bottom and won't stay in the solution). Each ingredient has a different solubility - salts are very soluble, gold isn't.

There's a funny joke to remember this - If you aren't part of the solution, you're part of the precipitate. Okay, maybe it's only funny to us chemistry geek types! 

If you see something that says it's water or oil soluble, that means it will dissolve completely in the water or oil. If you put an oil soluble ingredient into water, you'll see that lovely mass of oil floating at the top pretty soon!

When something is dispersible, it means it will stay suspended in the mixture, but it will always be separate and won't form a homogeneous solution. When we use fragrance or essential oils in something like a body wash, the oils aren't dissolved but suspended. We don't notice a huge difference unless those oils separate out and form an oily mass on top of the body wash, which can happen if you use too much! So if something is a disperser, it means it keeps the ingredients suspended in the product and you won't get a homogeneous solution. You might not notice this - you don't notice a water soluble ester in a body wash because it looks like a homogeneous solution, but there might be tiny little fat molecules that are separate from the actual solution.

Emulsification is a much more complicated process and you can find out more about it here and here.

11 comments:

Anonymous said...

Hi,

I made a DIY cleansing oil using 25% castor oil and 75% sunflower oil. Upon using it, I found that it was not water-saoluble as the storebought cleansing oils I normally use. I am not sure how to remedy this, will adding Olive Oil PEG 7 Esters make it soluble? And if so, how much or what percentage should I add?

Hope you can help me with this, as I have been going crazy with all formula and chemistry words all over the net!

Mich said...

LOL...the precipitate...
I actually know several people who would like that one!
Thanks for the giggle!

Susan Barclay-Nichols said...

Hi Mich! I knew someone would get it! I love chemistry jokes.

Two atoms walk into a bar. One says, "Oh no! I think I gained an electron!" The other one says, "Don't be so negative!"

Hi Anonymous. PEG-7 olivate will make it more water soluble, but I guess the question is really what store bought product are you using? It might give us a better an idea of what you are trying to make!

Anonymous said...

I normally use Laventine's Olive Oil Forte Cleansing Oil, which has Olive Oil, Olive Oil Esters, Olive Squalene, Vitamin E as the ingredients.

I did some research and found out that sunflower oil can be substituted for olive oil to make it lighter yet still moisturizing, while castor oil has some anti-bacterial properties. The combination will make a good cleansing oil, but because I do not like the whole Oil Cleansing Method where one puts on a steamed washcloth to rinse the oil on the face, and I have been used to the water-soluble kind of cleansing oil where the oil just comes off once I rinse it with water (but still retaining some oil to moisturize the skin), I am now looking for natural ingredient/s to make my mix water-soluble.

I'm not sure if I can just add a small amount of the Olive Oil Esters to make my concoction water-soluble, or there's a formula/percentage so that the mix would work, like HLB requirements or something to that sort. Concepts like "self-emulsifying oils" or "solubilizing oils (micro-emulsifying) into water oil" and their required HLB values are confusing me. I tried making a mix with an HLB value of 13 (since I read that this is required for solubulizing oils into water) but I would have to reduce the % of the sunflower oil to a significantly low amount. I am not even sure if I understand this concept at all.

Hope you can help me!

Thanks =)

Andrea Butje said...

Thank you for this excellent post! It was very helpful and offered such clear explanations of the differences between a soluble, disperser and emulsifier! Love the joke!!

Meaue said...

Anon:

Lotioncrafters has a recipe that calls for 75% olive oil, 12% squalane, 12% Cromollient SCE and 1% Vit E. This should give you the %'s for a "rinse off" OCM formula. It states that this recipe can be tweaked by increasing the oil for leaving more oil on the face or increasing the Cromollient SCE for leaving less oil on the face. Adding more squalane will thin the product more. You can also use caprylic/capric triglycerides instead of squalane, or substitute the olive oil for other oils. Hope this helps.

Anonymous said...

Thank you very much!!! =)

I have a question though, what is Cromollient SCE made of? Is it also natural? And will it be alright for it to be substituted by the PEG7 Olive Oil Esters?

Susan Barclay-Nichols said...

Hi anonymous. I think it is derived from myristic acid, a fatty acid found in coconuts (C14) or other saturated butters like shea, mango, or cocoa butter. I'm not sure of what the definition of natural is anymore, but I would call this a processed product that isn't natural in the sense of being like shea butter or coconut oil.

Having said that, I have seen people justify calling it natural by saying it's derived from coconuts. But then again, I've seen people say that dimethicone is natural because it is derived from sand, which is why I have no idea what natural means any more. If you're looking for natural, I wouldn't consider PEG-7 olivate natural either.

Whether you can substitute it depends on what you're making. If you want to use them as emollients in something like a body wash, shampoo, body mister, or other watery product, then you can substitute it. If you want to use it to disperse something into a watery product, then no, you can't substitute it. I realize this is a very generic answer, but if you know what product you want to make, I can offer more information.

Anonymous said...

I understand what you mean, nowadays organic and natural yet processed all are used differently.

I was referring still to the cleansing oil.

Especially now that you have told me Cromollient SCE is made from coconuts and other oils, and coconut and cocoa butter as I have read, are high-clogging or more comedogenic, as compared to the low-clogging oils such as castor, sunflower and olive -- would it be okay to substitute the Cromollient SCE with the Olive Oil Esters? Will the formula still work as a rinse-off OCM?

Susan Barclay-Nichols said...

Hi anonymous. You can use any type of oil in the oil cleansing method, although the most commonly seen one is castor oil. The key is getting it off your skin. All oils will moisturize, but not all of them will feel nice on your skin neat! That's where the Cromollient or PEG-7 olivate comes in - both will help solubilize the oils and remove them (heck, you can use polysorbate 20 or 80 in the same role and they have a score of 0 out of 3!) I'd think 10% to 15% of either ester will work well.

You can't really extrapolate the comedogenicity of the esters based on the original oil as it has been processed to become a completely thing although it's still based on myristic acid. It isn't necessarily from coconuts - it could be from coconuts, shea, cocoa, mango, or other saturated butters. Also, the comedogenicity depends on the dilution of the ingredient - something that is really comedogenic at 100% or 75% might drop when used at 5% (like IPP, for instance). I can't find any information on its comedogenicity on either of these ingredients, though, so you'll just have to experiment on your skin and chart the results.

Anonymous said...

Now I am thinking whether to use Cromollient SCE or PEG-7 Olivate. What are the pros and cons of each? Any difference between the two in terms of gentleness on the skin?

Read that Cromollient SCE's INCI name is 100% active alkoxylated di-ester of Myristyl Alcohol. Now that's something I don't understand and can't pronounce, I would have to say I am now leaning towards the PEG-7, LOL. At least that I know is from Olive Oil.

Btw, what do you mean when you said polysorbate having a score of 0 out of 3?

Thank you so much for sharing knowledge that we non-chemists would not usually understand =)