Micellar and Silver Nanoparticle‐Induced Spectral Behavior of Naphthyl Boronic Acid in Aqueous Surfactant Systems

The interactions of naphthyl boronic acid (NBA) with cationic, anionic, and nonionic surfactants, as well as trimethoxymethylsilane (TMS), were investigated in both the ground and excited electronic states. Silver/NBA/surfactant nanomaterials were prepared, and their optical properties were examined using UV–visible absorption and fluorescence spectroscopy. The critical micelle concentration (CMC), binding constants, and Gibbs free energy changes (ΔG) associated with NBA–surfactant complex formation were evaluated to understand the micellization process. As the surfactant concentration increased, the absorption spectra of NBA exhibited a gradual decrease in absorbance with little or no change in the absorption maximum. In contrast, the fluorescence spectra showed noticeable variations in both the emission wavelength and fluorescence intensity, indicating changes in the local microenvironment surrounding the NBA molecules. Progressive changes in both absorption and emission characteristics confirmed the interaction of NBA with the surfactant aggregates. The negative Gibbs free energy values demonstrate that the association between NBA and the surfactants occurs spontaneously and is thermodynamically favorable under the experimental conditions. In the ground state, NBA displayed the strongest binding affinity toward sodium lauryl sulfate (SLS), whereas cetylpyridinium chloride (CPC) exhibited the highest affinity in the excited state. Furthermore, incorporation of NBA, individual surfactants, and NBA–surfactant assemblies into silver nanoparticles resulted in distinct red and blue shifts in both the absorption and fluorescence maxima, reflecting changes in the electronic environment arising from nanoparticle–surfactant interactions.