Dresden 2011 – wissenschaftliches Programm
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O: Fachverband Oberflächenphysik
O 68: Polymeric biomolecular films
O 68.2: Vortrag
Donnerstag, 17. März 2011, 11:30–11:45, WIL B122
Synthesis of 2D COFs through exfoliation and coalesence of nano-crystalls — •Jürgen F. Dienstmaier1, Wolfgang M. Heckl2,3, and Markus Lackinger1,2 — 1Ludwig-Maximilians-University and Center for NanoScience (CeNS) — 2Deutsches Museum — 3Department of Physics, TUM School of Education, Technical University Munich
Self-condensation of Benzene-1,4-diboronic acid can yield highly crystalline Covalent Organic Frameworks (COF). In the COF-1 structure, monomers are covalently interlinked into two-dimensional sheets which are then stacked along the c-axis. These sheets are comprised of a hexagonal alternating arrangement of phenyl and boroxine rings and are an ideal model structure for 2D COF variants. In this contribution we demonstrate a new approach to first synthesize nanocrystalls of COF-1. The product of this synthesis was independently characterized by PXRD, TGA, IR-, and Raman-spectroscopy. After exfoliation, two-dimensional nanocrystalline flakes, whose structure correspond to a single layer of COF-1, are dispersed in solvent and deposited onto a substrate. STM imaging under ambient conditions reveals full monolayer coverage of nanocrystalline COF flakes with well ordered internal structure. Tempering of these highly polycrystalline structures results in ripening and increasing domain size.