Síntesis controlada de nanoestructuras de oro tipo dogbone con CTAC

Resumen

This work reports the controlled synthesis of anisotropic gold nanoparticles with a dogbone-like morphology using the seed-mediated growth method. The main innovation lies in the substitution of the conventional surfactant cetyltrimethylammonium bromide (CTAB) with the more economical cetyltrimethylammonium chloride (CTAC), resulting in a substantial reduction in synthesis cost. The lower chloride content inherent to CTAC was compensated through the controlled addition of hydrochloric acid (HCl) in varying amounts, thereby optimizing the anionic concentration and colloidal stability of the system. A systematic decrease in nanoparticle length was observed when the total reaction volume was reduced from 1 mL to 400 µL, while the waist diameter remained constant. This volumetric adjustment produced a progressive reduction in the aspect ratio (L/D), demonstrating direct geometric control through reaction scale and ionic availability. The results confirm that CTAC can effectively replace CTAB for the synthesis of anisotropic gold nanoparticles, preserving morphology and uniformity while decreasing the cost per reaction by up to one order of magnitude.