1. CAREER: Development of Novel Ternary Copolymer Assemblies Robert B. Grubbs, Dartmouth College, DMR-0239697 Linking chemically dissimilar polymer chains together into block copolymers leads to materials that form interesting self-assembled structures in bulk and in solution in which specific chemical functionality is localized to well-defined nanometer-scale regions in three- dimensional space. We are attempting to use this behavior to locate multiple nanometer-scale metallic particles in polymer films. Alkyne-functional block copolymers have proven to effective for the localization of cobalt-functional polymer blocks to defined regions of a polymer film. Organization of cobalt-containing domains might allow the preparation of high capacity magnetic storage devices (see Grubbs J. Polym. Sci. 2005 ). We have begun to examine systems resulting from attachment of alkyne-functional diblock copolymers to gold nanoparticles. These can be prepared either by generation of gold nanoparticles in the presence of end-functional copolymers (Figure 1) or by exchange of end- functional copolymers with ligands on pre-formed gold nanoparticles. Treatment of these latter particles with cobalt carbonyl followed by heating leads to the formation of cobalt particles studded with gold nanoparticles (Figure 2). We are currently investigating the self-assembly of these materials and their magnetic properties. Figure 2. Transmission electron micrograph of composite gold-cobalt nanoparticles resulting from heating (110 °C, 20 h) of gold nanoparticles to which thiol-terminal cobalt carbonyl/alkyne-functional block copolymers have been ligated by exchange with dodecanethiol ligands. Figure 1. Synthesis (a) and transmission electron micrographs at two different magnifications (b, c; cobalt-rich regions appear dark and gold nanoparticles appear darker) of cobalt carbonyl/alkyne-functional block copolymer-coated gold nanoparticles prepared by reduction of gold salts in the presence of thiol-terminal block copolymers.

2. CAREER: Development of Novel Ternary Copolymer Assemblies Robert B. Grubbs, Dartmouth College, DMR-0239697 Education and Outreach: Five Ph.D. students, Laura Sessions (6 th year), Yu Cai (5 th year), Qing Xia (4 th year), Anna Greene (2 nd year), and Addison Bouchard (2 nd year); one post-doc, Dr. Anand Sundararaman; and four undergraduates, Liz Jackson (’06), Kristen Limbach (’08), Jeff Garber (’09), and Ellen Robertson (REU student from Kalamazoo College), are currently involved in this research. Jesse McCann (now a Chemistry Ph.D. candidate at U. Washington), Kjell Ericson, Jakub Wegrzyn (MS program in Chemical Engineering Practice at MIT), Benjamin Cohen (UC San Francisco Medical School), and Gloria Sheng (MS program in Nano- and Microtechnology Enterprise, Cambridge) prepared Honors Theses based upon their work in the lab as undergraduates at Dartmouth. Lindsey Saunders (Brandeis University), Ben Stokes (U. Wisconsin), Andy Wills (Carleton College), and Analiz Rodriguez (New College, FL) have participated in aspects of this research through the Dartmouth NSF-REU program in Molecular Materials. A recent group photograph (6/2006) appears to the right. From the left, Qing Xia, Yu Cai, Laura Sessions, Anand Sundararaman, Anna Greene, Barney Grubbs, Gloria Sheng, and Addison Bouchard are pictured. A graduate/upper-level undergraduate course in synthetic polymer chemistry (Chemistry 109) has been developed and will be offered for the second time in the spring of 2007. An informal biannual meeting, the New England Polymer Chemistry Workshop, has been developed in collaboration with researchers in the greater geographical area. These workshops have provided professors, post-docs, graduate students, and undergraduates with regular opportunities to discuss their research with others and is leading to the development of collaborations across institutional lines.