PH
The pH (potential hydrogen) determines whether an aqueous mixture is acidic, neutral, or basic. The pH is measured on a scale of 1 to 14:
Recommended pH:
For shampoo: 5 to 7
For shower gel: 5 to 7.5
For a detangling hair care product: 4.5 to 5
For intimate hygiene products: 4.5 to 5.5 for women of childbearing age, 6.5 to 7 for young girls and menopausal women
Surfactants
Definition: A surfactant is a compound that modifies the surface tension between two surfaces (i.e., the tension that exists at the interface between two media). Surfactant compounds are amphiphilic molecules, meaning they have two parts with different polarities: one lipophilic part that has a strong affinity for fats, and one hydrophilic part that has a strong affinity for water.
Functions of surfactants: depending on their structure, surfactants can have different functions:
Detergent (or cleaning) agent: capable of removing impurities or dirt
Foaming agent: acting on the water-air interface, this type of agent allows a large volume of gas to be dispersed in a small volume of liquid, thus forming foam
Wetting agent: this type of agent allows a liquid to spread more easily over a solid
Emulsifier: an emulsifier allows two immiscible liquids, such as water and oil, to be mixed together to form an "emulsion."
Conditioning agent: this type of surfactant combines with keratin or skin to make them smooth and silky
Types of surfactants: there are four types of surfactant compounds, which are grouped according to the nature of the hydrophilic part:
Anionic surfactants: the hydrophilic part is negatively charged (anion). These surfactants are particularly effective as detergents.
Cationic surfactants: the hydrophilic part is positively charged (cation).
Amphoteric surfactants: these have two charges, one positive and one negative.
Nonionic surfactants: the molecule has no charge. These are our preferred surfactants because they enable us to manufacture skincare products that are well tolerated by the skin.
