According to the study, hair dye can make consumers more prone to damage and increase the likeliness of a bad hair day, meaning they require specific shampoo formulations.
The research published in the International Journal of Cosmetic Science, details how microscopic analysis of hair revealed that the chemicals used to dye it can strip away the natural oily layer that protects it, however, P&G scientists believe they have shown how to create liquid crystals that can stick to the negatively charged hair.
“It is proposed that the liquid crystal structure promotes the deposition of a hydrophobic polymer/surfactant layer on the hair surface. This increase in hydrophobicity changes the surface energy of the hair and allows for more effective deposition of the silicones,” explained the study.
Using methods known as atomic force microscopy, which generates nanoscale images, and micro-CT scanning the scientists analysed the interactions between the chemicals and hair fibres.
They found the most significant differences were between thick, fine and colored hair with individual hairs left electrically charged and attracting water, which means that uncharged chemicals such as silicone, added to shampoo making it easier to manage, will no longer stick.
The researchers also found that using traditional shampoo and conditioner products failed to repair the damage to the hair as the chemicals they contained, such as silicone, could not stick to the negatively charged hair, meaning that a lot of the product applied is not actually of any use.
“Oxidatively damaged hair, above others, needs effective conditioning to protect the hair from environmental and mechanical damage as the oxidative process has left it more prone to damage,” explained the researchers.
“However, the surface characteristics of the color-treated hair make formulating a conditioning shampoo a challenge.”