Betaine Alternatives, Foaming Properties
While searching for betaine alternatives, I came up with sodium cocoamphoacetate and disodium cocoamphodiacetate as possible candidates. Based on my (albeit limited) understanding, betaines are often used in shampoo and body wash for the following benefits:
As I am still learning about the different properties of surfactants, I decided to do a blender test on all of the ones that I own. I have heard that amphoterics are better at foaming than non-ionics, but less than anionics. This was confirmed in my blender testing. What surprised me, however, was that-at least for sodium cocoamphoacetate and disodium cocoamphodiacetate-this was only true at highly alkaline pH. When I performed blender tests at acidic (<6) and neutral (7) pH, the amphoterics produced less foam than non-ionics. I know that the charge of an amphoteric changes based on pH, but what I didn’t know was how that affected foaming characteristics.Anyway, here are my questions:
- Improved mildness
- Improved foaming
- Improved viscosity
Sorry for so many questions; I’m still learning
- Does cocamidopropyl betaine perform any better at the acidic pH that we would normally aim for when formulating shampoo?
- Similarly, is there a better alternative to the betaines that serves the same purpose?
- Is there some synergy that I’m missing, whereby betaines or amphoterics foam poorly on their own (in acidic conditions), but somehow still manage to boot foaming of other surfactants?
- Exactly how do these surfactants thicken? I see that claim for all three in my post, but I’m not sure how it works. Do they adjust the salt curve or is there something else?
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