Long carbon chain quaternary ammonium salts are cationic surfactants. They are used widely as conditioners to keep hair flexible and soft and to improve combability, among other benefits. Long hydrocarbon chain quaternary ammonium salts also carry a positive charge on their nitrogen atom, and thus have good affinity to hair. After shampoo and conditioner treatments, they remain deposited on the hair surface, which provides good combing, anti-static and detangling performance. However, long carbon chain quaternary ammonium salts are not compatible with anionic surfactants. They form complexes and precipitates in the formulation, which create instabilities. In some cases, modifications to the molecular structure can improve compatibilities—with the addition of ethylene oxide (EO) and propylene oxide (PO) groups, for example.
In contrast to cationics, alkyl phosphate esters are anionic surfactants, widely used in body washes and facial cleansers. Here, the authors combined the former quaternary ammonium structure with this phosphate structure to produce a surfactant with both positive and negative charges (i.e., an amphoteric structure), resulting in behenamidopropyl PG-dimonium chloride phosphate (BMDCP). Such long carbon chain quaternary salt-phosphate esters have desired amphoteric characteristics, in addition to preservative effects. This article reports the authors’ findings on the benefits of this material for hair care applications.
Materials and Methods
BMDCP is a naturally derived phospholipid composed predominantly of diester and triester phosphatides with multiple chain groups. Having an amphoteric character, it is compatible with most types of ingredients, including anionic surfactants. Here, the authors assessed its hair conditioning effects.