Gold Colloids from Cationic Surfactant Solutions. 1. Mechanisms That Control Particle Morphology
Citations Over TimeTop 10% of 2002 papers
Abstract
The mechanism of formation of gold particles by reduction of AuIII in solutions of alcyltrimethylammonium chloride surfactants was studied in the absence and in the presence of NaCl. AuIII anions interact strongly with trimethylammonium cations forming insoluble ion pairs (Torigoe et al. Langmuir 1992, 8, 59). Above the surfactant critical micelle concentration, the ion pairs are solubilized in the micelles returning to the solution. Gold particles were produced by photochemical reduction of the clear micellar solutions. The coupling between surfactant aggregation and inorganic crystallization phenomena in these systems was investigated using transmission electron microscopy (TEM), UV−vis, and time-resolved fluorescence spectroscopy. At concentrations close to the phase boundary of the L1 phase with the lyotropic liquid crystalline phases many gold particles have a threadlike morphology, as previously noted by Esumi et al. (Langmuir 1995, 11, 3285). The presence of NaCl modifies the micellar size and affects the gold crystallization process in surprising and unexpected ways, as evidenced by intermediate structures observed by TEM. Our observations support the idea that the formation of threadlike gold particles occurs primarily through a combination of crystal aggregation and specific crystal face stabilization and not through templating mechanisms.
Related Papers
- → Decyltrimethylammonium Bromide Micelles in Acidic Solutions: Counterion Binding, Water Structuring, and Micelle Shape(2016)14 cited
- → An observation of the coexistence of multimers and micelles in a nonionic surfactant C10E4 solution by dynamic light scattering(2008)13 cited
- → Optimizing the hydrodynamic radii and polydispersity of reverse micelles in the Triton X-100/water/cyclohexane system using dynamic light scattering and other studies(2006)21 cited
- → Theory of DNA–cationic micelle complexation(2012)15 cited
- → Imaging of Dihexadecylphosphate Vesicles by AFM and Counterion Effect on Their Size and Stability(1997)12 cited