BROADER IMPACT Undergraduate Research Experience: Nanocalorimetry

1. Magic Size Layer and Melting Point of Lamellar Silver AlkanethiolateLeslie H. Allen, University of Illinois – Urbana Champaign, DMR 1006385 “Magic Number Sizes” are interesting in materials physics and Solid State Chemistry because they exhibit unique underlying material properties. First discovered in vapor cluster beams in the 1970’s, they have also been observed in Indium clusters on surfaces by using Nanocalorimetry techniques developed in our group [Efremov, Allen, et al., PRL 2000, v85, 3560] and multilayer protected clusters with a Au core [Jadzinsky, et al., Science 2007, v318, 430]. Melting points of these 3-D spherical indium magic sizes are discrete and unique (see figure) and can be easily distinguished experimentally using Nanocalorimetry which has ultra-high sensitivity (monolayer). Recently we have developed chemical synthesis techniques that allow us to fabricate single and multiple 2-D lamella layers [Hu, Allen, et al., J. Amer. Chem. Soc. 2011, 133, 4367] and find that these magic sizes also show discrete and unique melting points (see Figure). These findings not only help us understand the basic stacking phenomena of solid state organic systems (alkanes and polyethylene) but also for biological systems such as cell-membranes and vesicles where we observed anomalous melting behavior [de la Rama, Allen, et al., Thermochimica Acta 2011, v522, 72].

2. Magic Size Layer and Melting Point of Lamellar Silver AlkanethiolateLeslie H. Allen, University of Illinois – Urbana Champaign, DMR 1006385 • BROADER IMPACT • Undergraduate Research Experience: Nanocalorimetry • Yiran Yan is modeling the structure of AgSRusing ChemDrawTM • Cornell Nanofabrication Facility (CNF) (2012) • - She trained in fabricating the nanocalorimetry sensors. • Her work has been highlighted in our presentations at various conferences. [2012 NATAS and 2012 ACS Fall Meeting] • She has gained valuable research experience in preparation for graduate school (2013). • PUBLICATIONS/CONFERENCES • Publications • Zhang, M., Kavanagh, K. L., Allen, L. H., et al., • J. Appl. Phys.,v111, 093516 (2012). • Hu, L., de la Rama, L. P., Allen, L. H., et al., • J. Amer. Chem. Soc., v133, (12), 4367, (2011). • de la Rama, L. P., Allen, L. H., et al. • Thermochimica Acta, v522, 72, (2011). • Invited Talks • 2012 Calorimetry Conference and International Conference on Chemical Thermodynamics (CALCON) • 2012 North American Thermal Analysis Society (NATAS) • - Presentations • 2012 American Chemical Society Fall Meeting • 2012 Materials Research Society Fall Meeting • 2011 Materials Research Society Fall Meeting Undergraduate Researcher Yiran Yan Modeling the layered structure of AgSR 2012 MRS Fall Meeting Symposium N, “Melting Point Depression and Magic Number Size in Lamellar AgSR”, L. de la Rama, Z. Ye, L. Hu, Y. Yan, M. Efremov, L. Allen.