Spectroscopic Investigations in Molecularly Organized Solvent Media. Part 4. Effect of Cosurfactant On the Ability of the Cetylpyridinium Cation to Selectively Quench Fluorescence Emission of Alternant Versus Nonalternant Polycyclic Aromatic Hydrocarbons

Abstract Fluorescence behavior is reported for 12 alternant and 15 nonalternant polycyclic aromatic hydrocarbons (PAHs) dissolved in aqueous micellar cetyltrimethylammonium bromide (CTAB) + cetylpyridinium chloride (CPC), Brij-35 + CPC and sodium dodecyl-sulfate (SDS) + CPC mixed surfactant solvent media. the three cosurfactants studied contain a cationic, nonionic and anionic headgroup, respectively. Experimental measurements indicate that the cetylpyridinium cation selectively quenches fluorescence emission of alternant PAHs. Emission intensities of nonalternant PAHs, with a few noted exceptions, remain essentially constant, irrespective of both CPC concentration and cosurfactant headgroup charge.