1. RUI: Stabilization of Gold Nanoparticles in Solution by Poly(vinyl alcohol) AdsorptionWei Chen, Mount Holyoke College, DMR 1005324 • INTELLECTUAL MERITS • Aggregation of gold nanoparticles (AuNPs) can be prevented by adsorbing a water-soluble and nontoxic polymer, poly(vinyl alcohol) (PVOH), to their surfaces in aqueous solution. The adsorption mechanism is studied as a function of polymer molecular weight and composition. • The second objective of the research is to examine self-assemblies of PVOH-AuNPs in the solid state. When aqueous droplets containing PVOH-AuNPs were cast on solid surfaces, drying-induced “coffee-rings” were observed. Table 1 shows macroscopic drying patterns on substrates with varying wettability (water contact angles) under ambient and high humidities. We are in the process of identifying parameters that affect the macroscopic drying patterns as well as the packing orders of PVOH-AuNPs on the nanoscopic level. Table 1. Drying patterns of PVOH-AuNPs (scale bar is 500 m) on substrates with different advancing and receding contact angles.

2. RUI: Stabilization of Gold Nanoparticles in Solution by Poly(vinyl alcohol) Adsorption Wei Chen, Mount Holyoke College, DMR 1005324 • BROADER IMPACTS • Education: Three undergraduate students, Lanhe Zhang 12’, My-Linh Nguyen 13’, and Yen Nguyen 13’, have been carrying out the NSF-supported research this year. Since last spring, Yen and My-Linh have been studying PVOH adsorption onto AuNPs in solution and self assemblies of PVOH-AuNPs in the solid state, respectively. Lanhe has worked on all aspects of the project since she joined the group in fall 2009. She has been a great mentor to the two junior researchers. She will focus on the effect of substrate chemistry on drying patterns of PVOH-AuNPs from sessile drops for her senior thesis. • Presentations given by undergraduates: • Zhang, Lanhe; Chen, W.* “Stabilization of Gold Nanoparticles in Solution by Poly(vinyl alcohol) Adsorption,” Abstractsof Papers of the American Chemical Society2010. Outreach: We recently formalized our long-term commitment to Hypatia, a local nonprofit organization helping pregnant and parenting teens to get GEDs. We run two workshops for the students every year and they have access to our laboratory space in the summer. In addition, when I was on sabbatical in Japan last fall, I ran a workshop for Japanese students on having a career in science as a female (see photo) and wrote an invited article on the subject for the Japanese polymer society journal.