Methods of increasing the volume of a fiber, such as mammalian hair, and/or altering the structure of a fiber with a chitosan polyelectrolyte complex

The invention includes methods of increasing the volume of a fiber by applying to the fiber a chitosan cross linked with or complexed to an aldehyde-bearing compound, and a polyanion. The fiber is then dried forming a chitosan polyelectrolyte complex on the hair that increases the dimension of the fiber. The fiber may be wet prior to application and may be a mammalian hair. Also included are method of semi-permanently altering the structure of hair that includes topically applying to hair a chitosan cross linked with or complexed to an aldehyde-bearing compound, and a polyanion. Also contemplated within the scope of the invention is a hair care polyelectrolyte complex that includes a chitosan cross linked with or complexed to an aldehyde-bearing compound, and a polyanion. Systems for hair treatment are also encompassed within the scope of the invention and include at least two formulations: a first formulation comprising a chitosan cross linked with or complexed to an aldehyde-bearing compound, and a second formulation comprising a polyanion. Such systems may be included in hair care kits.