Cationic cellulose nanocrystals enhance keratin adsorption to improve hair glossiness and thermal-photo protection

The functional chemicals in conventional personal care products may have negative effects on both human body and the environment, and natural proteins are gaining increasing attention as alternatives to functional chemical. However, due to the poor absorption of proteins on the surface of the hair, it cannot perform their function well. In this study, a protein-based multifunctional complexes, made of keratin and cationic cellulose nanocrystals by opposite charged-induction, were prepared for improving the glossiness and reducing hair thermal-photo damage. By changing the ratio of keratin and cationic cellulose nanocrystals in complexes, the optical properties and oil delivery property were studied. It was found that the protein-based complexes could improve the glossiness of substrate and have synergistic reducing UV transmittance, especially UVB. Besides, the complexes with high ratio of C-CNC were beneficial for the deposition of silicone oil onto hair. And after treated with the complexes or the resulting emulsion, the water evaporation of hair during heat treatment and the hair damage during light radiation were effectively reduced to improve the thermal-photo protection for hair. This study was expected to provide new design for improving adsorption of protein on the substrate and developing protein multifunctional application in personal care.