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Journey to the centre of your hair. A close-up look at L’Oréal research.

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Valérie Jeanne-Rose

The best innovations take time, as proven by the sol-gel technology developed by L’Oréal research. Behind the odd-sounding name is a revolution for fine hair. Read on to learn why.

Using silanes to strengthen your hair

Valérie Jeanne-Rose is a chemical engineer at L’Oréal’s advanced research centre in Paris. She joined the group in 1997 to explore solution-gelation or “sol-gel” technology. “Back then, the Group was looking for an innovative solution for fine hair that would be longer lasting than gels or sprays and that created a more natural look”, Valérie explains. Sol-gel processes are a chemical method used to turn a small basic molecule in solution into a solid vitreous gel. “This reaction takes place in nature, for example in some single-cell seaweeds and in some plants, such as nettles and bamboo.” Well known to manufacturers such as Saint Gobain, since 150 years, the process is used to create the titanium and silicon dioxides used in clear coverings or, more recently, in self-cleaning glasses.

“Silane is a fascinating molecule that hardens with water”

“What is special about this process is that it involves soft chemistry, by which I mean that it takes place at ambient temperature and the key reagent is water”, Valérie goes on. This is what caught her attention, as she spotted a potential application to hair. It took years of work on sol-gel technology to identify silane, a fascinating molecule that hardens immediately when it comes in contact with water and continues to harden once incorporated into hair. “But we still didn’t know how to fasten the molecule to the hair.”

Aminosilane and polyquaternium combine for a lasting effect

Valérie and sol-gels go back a long way. All told, she has spent 15 years looking at how to use silanes to treat fine hair. “In the first tests,. We needed to find a way to anchor it inside the hair fibre – a pretty tough job considering hair strands are only 60 microns thick.“ After hundreds of tests and many more hours logged in the lab, a solution was eventually found with filloxane, a member of the aminopropyltriethoxysilane family of silanes.

“Polyquaternium attaches itself to hair walls“

After introducing aminosilane inside the hair, the next job was to anchor polyquaternium, a polymer, to the surface of the hair shaft. The polymer is placed on the hair and the aminosilane holds it there from the inside. “Aminosilane acts like a skeleton combined with a magnet. When water is present, it polymerises and manufactures a material that attaches itself inside the hair strands, holding the polyquaternium on the surface.” This perfect combination provides a viable solution for dry hair. “When dosed correctly, the aminosilane /polyquaternium duo supports hair from the inside while restoring a natural and healthy look.”

Capillary revolution

“We soon demonstrated the beneficial effects of the combination in the lab”, explains Valérie. Results include healthier hair, a lasting reduction in friction, easier detangling and a better resistance to heat. “This is the innovation we have been waiting for a long time. Not only does aminosilane help to make fine hair more rigid, but when combined with polyquaternium, it prolongs the beneficial effects of the polymer even after several washes.”

L’Oréal’s marketing teams worked hand in hand with the advanced research centre throughout the project to prepare the final formula with just the right dose of the two ingredients. The applied research centres then took care of introducing it into creams, shampoos, serums and other products, and went on to develop solutions for all hair types, from dry to badly damaged. After 15 years of research and 15 patents, the Pro Fiber range is now taking Valérie’s innovation to certified hair salons.

The last word?

“Working with hair is a stimulating exercise that teaches patience and self-sacrifice. Creating a product that works well and that will help millions of women to feel better about themselves is something that I am very proud of.”

Research & Innovation | December 2015