Polymer Nanoparticles for the Release of Fragrances: How the Physicochemical Properties Influence the Adsorption on Textile and the Delivery of Limonene

The market of cosmetic and personal care products is continuously growing its impact. In particular, the products that are currently driving this growth have a strict connection with fragrances (e.g., perfumes, detergents, body creams, and softeners). Since the fragrances are volatile molecules, very often, they are encapsulated in polymeric nanoparticles (NPs) that mediate their release and hence prolong the fragrance perception. Toward this aim, it is highly desirable to maximize the interaction between the carrier and the substrate, which would avoid the NP desorption following scrubbing and repeated washing. In the case of laundry products, limited NP desorption is also crucial to prevent the accumulation of nanoplastics in the environment, which is nowadays strictly regulated. Therefore, a thorough study highlighting the influence of the different physicochemical properties of the NPs on their adsorption behavior is urgently required. In this work, we synthesized polymer NPs with different sizes, surface charges, glass transition temperatures, and degrees of cross-linking through emulsion free-radical polymerization to investigate how these parameters affect the NP adsorption onto a textile substrate (composition: 90% cotton/10% elastane). This study can provide interesting guidelines in the design of new fragrance delivery systems as well as in the optimization of those already adopted in the market. Finally, we investigated the possibility of loading and mediating the release in air of limonene, one of the most common odorous molecules in the cosmetic field, overcoming its well-known volatility.