1. CAREER: Development of Novel Ternary Copolymer Assemblies Robert B. Grubbs, Dartmouth College, DMR-0239697 Figure 1. (a) Synthesis, (b) transmission electron micrograph (cobalt-rich regions appear dark), and (c) atomic force micrograph (cobalt-rich regions appear brighter) of the cobalt-bearing block copolymer PS 185 - PTMSES 49 (M n ≈ 43 kg/mol; 44 wt% PS). 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 polymers have proven to effective for the localization of cobalt-functional polymer blocks to defined regions of a polymer film (Figure 1). Organization of cobalt-containing domains might allow the preparation of high capacity magnetic storage devices. (see Mîinea, et al. Macromolecules 2004 ; Sessions, et al. ibid. 2005. ) We have also prepared triblock copolymers that should form assemblies of vastly different sizes and shapes depending upon solution temperature (Figure 2). We are investigating these assemblies as potential nanometer-scale devices and as drug delivery vehicles. (see Wegrzyn, et al. J. Polym. Sci. A 2005 ; Aubrecht, et al. ibid. 2005. ) Figure 2. Atomic force micrograph of stimulus responsive amphiphilic triblock copolymer PEO-b-PNIPA-b-PI spin cast on a mica surface from a 1g/L solution in water. The size and shape of the assemblies suggests that they are hollow vesicular structures with the capacity to encapsulate water-soluble materials. (block M n s: PEO ≈ 2.0 kg/mol; PNIPA ≈ 2.2 kg/mol; PI ≈ 4.7 kg/mol).

2. CAREER: Development of Novel Ternary Copolymer Assemblies Robert B. Grubbs, Dartmouth College, DMR-0239697 Education: Three Ph.D. students, Laura Sessions (5 th year), Yu Cai (4 th year), and Qing Xia (3 rd year); one post-doc, Dr. Liliana Mîinea; and one undergraduate, and Gloria Sheng (4 th year), 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), and Benjamin Cohen (UC San Francisco Medical School) worked in the lab while undergraduates at Dartmouth. Lindsey Saunders (Brandeis University) Ben Stokes (U. Wisconsin), Andy Wills (Carleton College), and Analiz Rodriguez (New College, FL) participated in aspects of this research through the Dartmouth NSF-REU program in Molecular Materials. A recent group photograph appears to the right. From the left, Yu Cai, Barney Grubbs, Tim Stephan (former post-doc), Liliana Mîinea, Qing Xia, and Laura Sessions are pictured. Outreach: An informal biannual meeting, the New England Polymer Chemistry Workshop, has been developed in collaboration with researchers in the greater geographical area and is currently in its third year. These workshops provide 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.