Iron Gall Ink Revisited: A Surfactant-Free Emulsion Technology for Black Hair-Dyeing Formulation

Inspired by the redox reactions in preparation of iron gall ink that has been used Europe since Middle Ages, we developed a technology for forming oil-in-water emulsions, without any surfactants and emulsifiers, homogenizing mixture tannic acid, gallic Fe(D-gluconate)2, natural oil, which are all approved as cosmetic ingredients. Various plant-derived oils, such argan olive sunflower grape seed hemp peppermint rosemary ylang-ylang were an oil phase emulsion formation, fabricated emulsions exhibited capability black hair-dyeing. This surfactant-free combining hair-dyeing Fe3+–tannin complex with hair-fortifying property would have great impact on hair-cosmetic industry.