Silicon Chemistry 2: 207–216, 2003. DOI: 10.1007/s11201-005-6189-2 C  Springer 2005 Nano-scale templating using honeycomb-like poly(amidoamine-organosilicon) (PAMAMOS) dendrimer networks Petar R. Dvornic 1,∗ , Robert A. Bubeck 1 , Scott D. Reeves 1 , Jieming Li 1 & Lee W. Hoffman 2 1 Michigan Molecular Institute, 1910 W. St. Andrews Road, Midland, MI 48640, USA; 2 Dow Corning Corporation, Midland, MI 48686, USA ∗ Author for correspondence (e-mail: dvornic@mmi.org) (Received 13 December 2002; accepted 30 October 2003) Key words: copper partitioning, nano-scale templating, nanocomposites, PAMAMOS Abstract Two different methods for preparation of Cu 2+ -poly(amidoamine-organosilicon) (PAMAMOS) dendrimer-based network nanocomplexes were developed and small angle neutron scattering (SANS) and X-ray photoelectron spectroscopy (XPS) were used for elucidation of fine structure of the obtained products. It was found that the in situ preparation method, by which less than the limiting amount of Cu 2+ for the given dendrimer generation was complexed with dissolved dendrimer before cross-linking, enabled precise templating of copper into the nanoscopic polyamidoamine (PAMAM) network domains only. The limiting amount of Cu 2+ for networks with generation 4 PAMAM domains was found to be between 5 (by SANS) and 8 (by XPS) mass %, in good agreement with the 9 mass % value calculated for idealized perfect dendrimer structure. It was also found that exceeding this concentration limit resulted in partitioning of Cu 2+ ions into the organosilicon (OS) network domains as well, probably because of possible complexation of cations with siloxane oxygens. Consistent with this, the diffusion method always resulted in random distribution of Cu 2+ cations throughout the bulk of the penetrated network layer(s), but the depth of this penetration was time-dependent and it followed Type II diffusion kinetics. This enables convenient control of layer thickness and preparation of thin layers of metal-network nanocomplexes. XPS data strongly suggest preferential Cu 2+ -tert. N complexation with in the PAMAM network domains, and indicate an unexpected oxido-reduction process above a certain copper concentration (approximately 2 tert. N per Cu ion) that leads to the formation of Cu 1+ and N + species. Introduction In several recent publications we described how radially-layered poly(amidoamine-organosilicon) (PAMAMOS) dendrimers can be used as excellent precursors for the preparation of unique honeycomb- like dendrimer-based networks [1–3]. Depending on the exact composition and generation of the PAMAMOS dendrimers used, exact composition of the cross-linking reaction mixture selected, and the set of cross-linking reaction conditions employed, these networks may be obtained as elastomeric or plastomeric films, sheets, coatings or other objects containing hydrophilic and hydrophobic polyami- doamine (PAMAM) and organosilicon (OS) domains, [1, 4]. In addition to this, we also showed [4–6] that even in the solid state of such networks, their constitutive PAMAM domains are still able to exhibit characteristic chemical properties that they show when free of topological constrains in liquid dendrimer so- lutions [7–9]. Among others, these properties include their pronounced ability to attract and complex various electrophylic species, such as inorganic metal cations (Ag + , Cu + , Cu 2+ , Ni 2+ , Co 2+ , Pt 2+ , Pd 2+ , Cd 2+ , Fe 2+ , Fe 3+ , Au 3+ , Rh 3+ , Eu 3+ , Tb 3+ , Dy 3+ , Sm 3+ , etc.), organic dies or organometallic compounds [6]. Because of the nature of their dendrimer precur- sors, these PAMAMOS networks are expected to have nanoscopic domain morphology. However, much of our initial evidence [1–3] is inferred, was inferential