When hair is colored using an oxidative process (the process used to gain a permanent or semi-permanent effect such as bleaching) up to 70 percent of the natural protective layer is removed.
This natural layer provides a hydrophobic (water repelling) barrier which when removed allows water into the hair’s internal structure, hindering the deposition of traditional conditioning ingredients and leaving the hair shaft more prone to damage.
Including the cationic (positively charged) polymer, poly(DADMAC) (poly(diallyldimethyl ammonium chloride), into a shampoo formula can improve the hydrophobic quality of the hair shaft, but only if liquid crystal structures are present in the formulation, explained one of the researchers Jeni Thomas.
“It’s the liquid crystal structure that really enables the actual polymer poly(DADMAC) to change the characteristic of the hair,” she said.
Limits damage when hair is wet
The inclusion of the polyDADMAC/liquid crystal technology into a shampoo can help create a slip plane effect, she explained, helping the hair shafts slide over each other and not snag during the washing process.
This is particularly important because traditional silicone conditioning ingredients are less effective when the hair is wet, leaving the hair shaft very prone to damage. In addition, as wet hair swells, the already rough bleached hair shaft will become even rougher.
Helps conditioners stick to dry hair
In addition to protecting the bleached hair when rough, the liquid crystal model can also enable other conditioners to work better when the hair is dry as it creates a surface with which the conditioning ingredients can interact, explained Thomas.
“It is surprising to see how little of these conditioning ingredients are deposited on bleached hair in traditional products,” explained Thomas.
Although a very new development, the technology has hit the market as part of the recently upgraded Pantene expressions range and P&G plan to explore the full potential of the work.
The research was presented at the recent AAAS (American Association for the Advancement of Science) annual meeting.