Commercial clays in cosmetic formulations for hair care: Characterization and application to improve the mechanical properties of hair fibre

Although some studies suggest the benefits of clay minerals in hair treatments, limited research has addressed their effects on the mechanical properties of hair fibres. This study investigates the incorporation of two commercial clays (designated A and B) into solid shampoo and conditioner formulations and evaluates their impact on the mechanical performance of hair fibres. X-ray fluorescence spectroscopy (XRF) analysis of the clays revealed a high silica content. X-ray diffraction (XRD) analysis identified montmorillonite and nontronite phases in clay A, characterizing it as bentonite. In contrast, clay B exhibited a predominant muscovite phase with secondary phases of illite and chlorite. Fourier transform infrared spectroscopy (FTIR) confirmed the presence of typical vibrational modes associated with these clay minerals. UV-VIS spectroscopy showed strong absorption in the ultraviolet region for both clays. Formulations were developed with clay concentrations of 0.5%, 1.5%, and 3.0%, alongside a clay-free control. The addition of clays significantly enhanced the mechanical strength of the hair fibres, particularly clay B, which yielded a 94% improvement at 3.0% concentration. Combing force measurements also improved, indicating that the tested concentration effectively reduced frizz. Gloss measurements showed excellent enhancement across all formulations, with clay B increasing specular reflection by 56% at 3.0%. Overall, these findings demonstrate a promising potential for commercial clays to improve the mechanical and aesthetic properties of hair when incorporated into cosmetic formulations.