Gold nanoparticles confined in lamellar mesophases

A lamellar surfactant mesophase is used as a soft confinement medium for gold nanoparticles that are directly synthesized inside the lamellar mesophase by the radiolytic reduction of a gold salt incorporated into the water medium. By increasing the water layer thickness of the mesophase, spherical gold nanoparticles of increasing size are obtained. The same soft confinement medium is used to synthesize directly in situ by radiolysis gold nanorods (aspect ratio about 10). It is also shown that gold nanorods can be inserted by simple mixing into a sufficiently swollen lamellar phase. In all cases, the structure of the lamellar phase is preserved in the presence of the nanoparticles.