Encapsulation of ultraviolet filter into cationic polystyrene particles via miniemulsion polymerization with poly(vinyl alcohol)

In this study, diethylamino hydroxybenzoyl hexyl benzoate (DHHB)-encapsulated cationic polystyrene particles (PS-DHHB) were synthesized and dispersed in water using miniemulsion polymerization. Low-molecular-weight poly(vinyl alcohol) was employed as an emulsifier, facilitating both the formation of monomer droplets and the subsequent polymerization process. Importantly, the inclusion of polystyrene (PS) in the monomer droplet increased the solid content and acted as a stabilizing agent, thereby enhancing the encapsulation efficiency of DHHB. The synthesized PS-DHHB particles exhibited ultraviolet (UV) absorption properties closely akin to those of DHHB. Additionally, the introduction of aqueous alcohol, used as an antibacterial agent, did not lead to the leaching of DHHB from the PS-DHHB particles. The study further revealed that PS-DHHB adhered more effectively to hair compared to anionic PS-DHHB and was superior in mitigating UV-induced hair protein loss in the 320–400 nm range compared to cationic PS particles without DHHB. In summary, the study resulted in the development of water-dispersible PS-DHHB particles with significant applications in polymer science and cosmetics, owing to their efficient UV absorption and effective hair adhesion capabilities.