Self-Assembly of Ag₂S Colloidal Nanoparticles Stabilized by MPS in Water Solution

Self-assembly of colloidal Ag₂S nanoparticles (NPs) was studied in the presence of (3-mercaptopropyl)trimethoxysilane (MPS). Solutions with different molar ratios of Ag₂S/MPS were prepared. The appearance of nano- and microtubes was detected. Self-organized NPs were studied with optical microscopy, scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and high-resolution transmission electron microscopy (HRTEM). Silicon nuclear magnetic resonance spectroscopy (²⁹Si NMR) was used to study polycondensation of MPS molecules. Geometrical parameters of the nano- and microtubes depended on the molar ratio of Ag₂S/MPS. The scheme and mechanism of self-assembly of Ag₂S NPs in nanotubes in the presence of MPS were proposed. The effect of MPS on the preservation of the initial stoichiometry of Ag₂S NPs was discussed.