Fun with chemistry: Anionic, cationic, and non-ionic

Will writes....I'd love to learn more about the whole _____ionic thing and how it applies to lotions/cream, etc. I've read about it, and the more I read the more confused I become. How about dumbing it down and explaining it in your excellent fashion? Just wishing...

Wish no more, Will! When it comes to chemistry, you ask and I will write (and it's not just 'cause flattery works well with me!).

Anionic, cationic, and non-ionic refer to the charge on the ingredient in question. Non-ionic means it has a neutral charge. Anionic means it has a negative charge. And cationic means it has a positive charge.

Take a look at this picture. The head is the thing that carries the charge. If the charge on the head is negative - for instance, something like sodium laureth sulphate with a sodium ion on the head - it will be an anionic ingredient.

If the charge on the head is positive - for instance, something like BTMS-50 - it will be a cationic ingredient.

If the head carries both a positive and negative charge, we get a zwitteronic ingredient (something like our betaines or sultaines, which are also called amphoteric when we're talking about surfactants), which can be positive or negative depending upon the pH level of the product.

This chart really only applies to our surfactants, those with a hydrophilic head and a hydrophobic or lipophilic tail (not just bubbly surfactants, but anything that reduces the surface tension between the two phases of our products, like emulsifiers). If it doesn't fall into the category of surfactants, then we generally have a non-ionic ingredient.

Most of our foaming, bubbling surfactants are anionic or negatively charged. Quaternary cationic compounds like BTMS-50, cetrimonium chloride, cetrimonium bromide, and Incroquat CR, and cationic polymers are positively charged.

In lotions, most of our ingredients are non-ionic or neutrally charged, like our emulsifiers, fatty alcohols (like the cetyl alcohol molecule you see), fatty acids, oils, butters, extracts, hydrosols, humectants, and so on. So when it comes to lotions, we're dealing mostly with non-ionic ingredients.

You can add a cationic ingredient to a lotion - I do it all the time with things like cationic polymers (like polyquat 7, polyquat 10, polyquat 44, and honeyquat) or as our emulsifier, like Incroquat BTMS-50. Cationic ingredients are substantive, meaning they will adsorb to your hair or skin and are substantive. (For more information on substantivity, please click here.) You can add an anionic ingredient to a lotion, but I can't think of any I'd like to add (for instance, I really don't see adding something like SCI to a lotion, despite my love for it!)

You really don't need to worry about charges all that much when it comes to lotions because most of our ingredients are non-ionic and we can easily add some cationics to the mix without fear of any serious problems.

Why add cationic ingredients to a lotion or cream? Generally we add them to a lotion for the skin conditioning benefits (the whole substantivity thing). When we use Incroquat BTMS-50 as our emulsifier or add a cationic polymer to our lotions, we are increasing the skin conditioning features of the lotion (and in the case of honeyquat, we're also adding a humectant, so it's a bonus!)

As an aside, I've said this before but please indulge me for a moment. You cannot have a hair conditioner without a cationic ingredient. The very essence of a conditioner is that it adsorbs to the hair strand and offers substantivity. Without a cationic ingredient, you don't have a conditioner. You might have something else that your hair likes, but it isn't considered a conditioner. 

Do you have chemistry related questions? Ask away! And for more chemistry, please check out the "frequently asked questions" post to the right hand side of the blog!