Micro-patterns of Au@SiO2 core-shell nanoparticles formed by electrostatic interactions

In this paper, silica-coated Au nanoparticles (Au@SiO2) were prepared by the technique of vortex mixing. Subsequently, these monodisperse Au@SiO2 nanoparticles were functionalized by the silane reagents 3-aminopropyltriethoxysilane (APS) and 3-mercaptopropyltriethoxysilane (MPTS) respectively. Then, these NH2-terminated and SO32−-terminated Au@SiO2 nanoparticles were respectively assembled onto the substrates, which have been patterned with different self-assembly monolayers (SAMs), to form close-packed two-dimensional Au@SiO2 nanoparticle arrays by electrostatic interactions. The morphologies and the optical properties of Au@SiO2 nanoparticles with different silica-shell thicknesses were characterized by TEM and UV-vis. The compositions and zeta potentials of the functionalized Au@SiO2 nanoparticles were examined by X-ray photoelectron spectroscopy (XPS) and dynamic light scattering (DLS). The morphologies of the patterns formed on different templates were characterized by atomic force microscopy (AFM).