Self-assembled Au and Pt nanoparticles in Poly(methyl methacrylate).

Nanocomposites formed by metal nanoparticles self-assembled in an insulator matrix are of great technological importance. Applications include surface enhanced Raman spectroscopy based biosensors, optical devices, photovoltaic cells, and more. Self-assembling of nanocomposites using low energy ion implantation offers a fast and low cost process. We report here on our work on nanocomposites formed by very low energy ion implantation of gold and platinum nanoparticles into Poly(methyl methacrylate) (PMMA), with description of the nanoparticle evolution as a function of implantation dose. The Au-PMMA and Pt-PMMA nanocomposites were characterized by transmission electron microscopy, thus determining the nanoparticle density, their size distribution, and the distance between particles as a function of implantation dose. A comparison between Au-PMMA and Pt-PMMA reveals substantial differences in the formation processes of the nanoparticles. The results provide insight into basic nanoparticle formation processes, as well as crucial information important for design applications. In addition, the tunneling decay length ξ and the electron affinity ε of the implantation-modified PMMA were obtained using a new and simple approach.