Fully accessible gold nanoparticles within ordered macroporous solids

A multi-step approach was used for the preparation of macroporous polymer films (or inverse opals), in which fully accessible metal nanoparticles are Incorporated. The method consists of the synthesis of silica-coated metal nanoparticles; their sedimentation to grow ordered compacts; sintering to ensure physical contact between spheres; infiltration with an epoxy resin; and dissolution of silica with HF. The isolation of the nanoparticles is ensured because they are locked within a single hole, and the pore size can be controlled through the thickness of the silica shell.