Chemical Action of Surfactants in Shampoo

Chemical Action of Surfactants in Shampoo

What Are Surfactants? 

Surfactants are molecules that have both a polar and nonpolar region (known as an amphiphilic molecules).  This gives them the unique quality of being both hydrophilic (water “loving”) and hydrophobic (water “hating”).  Hydrophilic molecules are attracted to water and want to be in water surfaces while hydrophobic molecules are repelled by water and want to be away from it, thus they generally are attracted to oils or surfaces that are nonpolar or uncharged. 

These amphiphilic molecules are able to orient themselves so that their polar, or hydrophilic regions, are oriented towards the water interface while the nonpolar, or hydrophobic regions, are oriented towards the lipid/oil interface.  This is what makes surfactants so good at removing oils from hair.   

How do Surfactants Work in Shampoo?  

Surfactants have the big job of cleaning.  The main function of them is to clean the hair of oils, skin particles, and other dirt and grime that you come into contact with in daily life.  In most shampoos, alkyl ether sulfates are used as the main surfactant.  The cleansing process of surfactants within shampoos goes through four main steps to remove oil/sebum:

  1. Roll-up
  2. Spontaneous emulsification
  3. Penetration
  4. Solubilization

Roll-up reduces the interaction between oil and water and hair and water causing the oil to separate from the hair.  Spontaneous emulsification takes the separated oil and turns it into droplets. 

Penetration pulls these droplets from the hair.  Finally, solubilization causes the oil to transform into micelles, which are essentially molecules that form a sphere with the nonpolar tails on the inside and the polar heads on the outside facing the water.  The micelle then detaches and is rinsed from the hair with water! 

Removal of the big stuff, like skin particles, dirt, and other solid particles occurs through what is known as surfactant spreading forces.  This process forces water in between the particles and the hair which prevents the solids from re-depositing in the hair after the shampoo has removed it.   

 Looking for Surfactant Products?

Do you have more questions regarding surfactants?  Want to learn which surfactants will fit your needs?  Contact Bulk Chemicals 2 Go to learn more!