Surfactants

Surfactants help remove dirt, oil, and buildup from hair. This is a group that includes detergents like sulfates as well as many non-detergent surfactants like behentrimonium chloride.

Types of surfactants

On a science level, there are several main types of surfactants:

• Anionic surfactants: These are the strongest type and include sulfates. They have a negatively charged hydrophilic (water loving) head. In chemistry, opposites attract, so this negative charge attracts positively charged dirt and oils to help remove them. Some of the oils on hair are good, so this isn't necessarily a good thing! They can also cause an increase in negative charges on the hair, which can make it frizzier.
• Cationic surfactants: These gentle surfactants are the opposite of anionic as they have a positively charged hydrophilic head. They usually aren't used on their own since they aren't very effectively at cleaning. They are effective at balancing out the negative effects of anionic surfactants.
• Amphoteric surfactants: These are weird ones, they can be positive OR negative depending on the surrounding pH. This adaptability means that when on skin and hair, which are mildly acidic, they are cationic (positively charged) gentle surfactants, and otherwise they are anionic (negatively charged) stronger surfactants
• Nonionic surfactants: These are neutral and include many things that CurlsBot doesn't classify primarily as surfactants such as fatty alcohols. Since fatty alcohols are mainly used for their emollient properties, CurlsBot sticks them in emollient alcohols.

An important thing to remember is that each type of surfactant is rarely used by itself. Most hair products include different surfactants that work together to cleanse without stripping hair or irritating the scalp.

How CurlsBot classifies surfactants

CurlsBot divides surfactants into three groups

• Sulfates: These anionic surfactants are in their own group because they are the type of detergents that the curly hair community most wants to avoid
• Soap: Another anionic surfactant, soap is in its own group because of its uniquely bad properties (causing buildup, harshness, and alkaline pH)
• Mild surfactants: These are widely recognized by the curly hair community as gentle
• Other surfactants: These don't fit easily into either group, or CurlsBot is still researching them