Multilayer nanoreactors for metallic and semiconducting particles

Multilayer thin films of sequentially adsorbed polyelectrolytes were utiliz ed as nanoreactors for both metallic (Ag) and semiconductor nanoparticles ( PbS). Polyelectrolyte multilayers with a controlled content of free carboxy lic acid binding groups were fabricated with weak polyelectrolytes via suit able pH adjustments of the processing solutions. These groups were then use d to bind various inorganic ions that were subsequently converted into nano particles. Spatial control (at the nanoscale) over the growth of the nanopa rticles was achieved via the use of multilayer heterostructures that also c ontain bilayer blocks that are not able to bind inorganic ions. These "nonb inding" bilayers were fabricated from strong polyacids such as poly(styrene sulfonic acid). TEM imaging of the nanoparticles within the multilayer thi n films indicates that the polycation and polyanion layers of these films a re highly interpenetrated.