Multifunctional Profragrances: Hydrolyzable Quaternary Pyridinium Surfactants for Dual-Controllable Perfume Release

The multifunctional chemicals with structural diversity are particularly attractive for various applications. In this study, we present a series of surfactants featuring the chemical structure of quaternary pyridinium salts (QPSs), wherein two types of alcohol fragrance molecules are linked to QPSs via ester bonds and acetal moieties. These profragrances exhibit multifunctional properties, including exceptional surface activity, antibacterial capability, and effective fragrance release performance. A notable feature of this system is their dual-controlled release of the perfume mixture of two different alcohols. In this context, the surface tension of the QPS was determined with the critical micelle concentration (CMC) ranging from 0.0313–0.4349 mmol L^–1 and a γ-CMC value of 19.4–26.1 mN m^–1. The minimum inhibitory concentration (MIC) tests demonstrated significant antibacterial properties, particularly against Gram-positive bacteria. Gas chromatography with headspace solid-phase microextraction was employed to test the release performance of profragrances in both the solution and the surface of cotton. The controlled release of individual fragrance alcohols under alkaline conditions resulted in a long-lasting scent, while the simultaneous release of two flavors was achieved under acidic conditions. Moreover, the QPSs were shown to be an effective fragrance delivery system for textiles.