Environment-Responsive Micellization and Functional Behavior of Cetylpyridinium Chloride in Applied Systems: A Comprehensive Review

Abstract

Cetylpyridinium chloride (CPC), a cationic surfactant belonging to the class of quaternary pyridinium salts with a sixteen-carbon alkyl chain, has attracted considerable attention due to its well-defined structure and notable biological efficacy, including antibacterial, antiviral, and antiseptic activities. Owing to its amphiphilic nature, CPC is suitable for diverse applications involving interfacial and micellar systems, and it is also widely studied as a fluorescence quencher and as a reaction medium. Its distinctive micellization behavior, governed by molecular structure and influenced by environmental conditions and additives, makes it a particularly versatile system. The micellar properties of CPC vary significantly with system composition, showing remarkable deviations in mixed micelles, solvent media, and in the presence of counterions, polymers, and drugs. Key parameters such as aggregation number, micelle morphology, counterion binding, and thermodynamic characteristics provide valuable insight into its behavior. A comprehensive understanding of these parameters and interactions highlights CPC as a tunable surfactant with versatile physicochemical properties, making it a promising candidate for scientific formulations, colloidal chemistry, and various industrial applications. In summary, this review discusses the micellization behavior of CPC across various systems and the factors that influences its micellization process.