Date: Thursday, October 21, 2021
Time: 1:00 pm - 2:30 pm EST

Plenary Lecture

Speaker: Dr. Brent Nannenga, Arizona State University

Title of Talk: Microcrystal electron diffraction (MicroED): Methods and applications

Abstract: A common barrier to high-resolution structure determination is the growth of large well-ordered crystals. Electron diffraction is capable of producing diffraction data from crystals that are orders of magnitude smaller than those needed for conventional X-ray crystallographic experiments. In this presentation, the technique of microcrystal electron diffraction, or MicroED, will be described, which allows the collection of high-resolution diffraction data from extremely small nano and microcrystals. MicroED methods will be described along with representative applications where MicroED was used for high-resolution structure determination.

Time: 1:00 pm EST

Short Talks

Speaker: Dr. Austin Evans, Columbia University

Title of Talk: Two-Dimensional Polymers and Their Applications

Abstract: Two-dimensional polymers (2DPs) are a unique macromolecular architecture that combine covalent connectivity, permanent porosity, and structural regularity. Recently, synthetic advances have led to the production of 2DPs as single-crystals and high-quality films, both of which are ideal for property and device measurements. Here, I will discuss recent findings regarding the thermal, mechanical, optical, and electronic attributes of macromolecular sheets. I will also describe first-generation 2DP-based devices, which show promising combinations of properties not accessible with other material classes.

Time: 1:40 pm EST

Speaker: Shihao Zang, Sacanna Group, New York University

Title of Talk: Colloidal Mineralogy

Abstract: Hundred-micron binary crystals could be rapidly self-assembled by generic colloids through Polymer-Attenuated Coulombic Self-Assembly (PACS) developed by us. PACS uses molecular spacers to tune the attractive overlap of electrical double layers between oppositely charged colloids, allowing us to direct particles to disperse, crystallize, or become permanently fixed on demand. Binary colloidal crystals isostructural to CsCl, NaCl, AlB2, and Th3P4 are selected according to particle size ratios and stoichiometry. Hoppering and twinning could manifest in colloidal crystals as well. More interestingly, the crystal nucleation, growth, and development of macroscopic crystal habits could be monitored in situ. Our findings reveal more complex crystallization pathways where crystals do not form directly but are generated via metastable condensate precursors - particle blobs with irregular shapes and poor or no crystalline order. The blobs grow by coalescence and either develop into mature faceted crystallites or are eaten up by larger crystals via Ostwald ripening or fusion.

Time: 2:10 pm EST