Substantivity is defined as “an adsorption phenomenon by which materials that have opposing charges or like composition are more readily adsorbed onto or attracted to its surface and, once there, resistant to subsequent rinse-off.” In other words, a material that is positively charged – like our cationic ingredients – will be attracted to the surface of our hair, which is negatively charged or anionic.
You can learn more by clicking here to read the post on adsorption and substantivity.