Influence of anionic surfactants on coacervation with cationic guar gum for hair care applications.

Objective: To assess the impact of anionic surfactants on the formation of coacervates with cationic guar gum and their subsequent effects on hair care.

Methods: Coacervates were prepared using ionic precipitation techniques involving four anionic surfactants: sodium lauryl sulfate (SLS), sodium lauroyl sarcosinate (SNL), sodium lauryl sulfoacetate (SLSA), sodium cocoyl isethionate (SCI) and cationic guar gum. Viscosity, spreadability and stickiness sensory analysis were conducted with a panel of volunteers. The coacervates were freeze-dried, and their physicochemical properties were analysed using Raman and Fourier transform infrared spectroscopy, scanning electron microscopy and thermogravimetric analysis.

Results: Coacervate formation and stability were dependent on the CGG-to-surfactant ratio, with 0.5% CGG/0.5% surfactant producing the most stable, uniform structures. Spectroscopic analyses confirmed stronger electrostatic and hydrogen bonding interactions at higher CGG concentrations, facilitating greater polymer-surfactant integration. Thermal analysis showed that balanced CGG/surfactant ratios enhanced coacervate stability, while excess surfactant led to lower thermal resistance and weaker deposition. SEM images revealed superior adhesion and homogeneous coverage on damaged hair fibres at 0.5% CGG/0.5% surfactant, suggesting better conditioning effects compared to lower polymer content.

Conclusion: The findings emphasize that coacervate stability, deposition efficiency and adhesion to hair fibres are optimized when CGG and surfactants are present in balanced ratios. The 0.5% CGG/0.5% surfactant formulation consistently exhibited superior stability, coverage and interaction with damaged hair, reinforcing its potential as an effective conditioning and protective system. These insights provide a foundation for improving coacervate-based hair care formulations, ensuring enhanced performance and long-term benefits.