Dresden 2006 – wissenschaftliches Programm
Bereiche | Tage | Auswahl | Suche | Downloads | Hilfe
O: Oberflächenphysik
O 38: Adsorption V
O 38.12: Vortrag
Donnerstag, 30. März 2006, 17:45–18:00, TRE Phys
In-situ Alteration of Bimolecular Hydrogen-bond Networks — •Lorenz Kampschulte1,2, Markus Lackinger1, Tova Adlerstein2, Stefan Griessl1, George W. Flynn2, and Wolfgang M. Heckl1,3 — 1Dept. Earth and Environmental Sciences, LMU München, Theresienstr. 41, 80333 Munich, Germany — 2Dept. of Chemistry, Columbia University, New York, New York 10027, USA — 3Deutsches Museum, Museumsinsel 1, 80538 Munich, Germany
Bimolecular monolayers were grown by spontaneous self-assembly from solution at the liquid-solid interface and subsequently investigated by Scanning Tunneling Microscopy (STM). The co-adsorption of two different molecules, BTB (1,3,5-benzenetribenzoic acid) and TMA (trimesic acid) in open (loosely packed) networks was studied in two different solvents (heptanoic and nonanoic acid). Altering the absolute and relative concentrations of the two compounds in binary solutions resulted in phases with six different structures. Their cavity size ranges from 1.1 nm for a structure solely composed of the smaller TMA molecules up to 2.8 nm for a pure BTB network. All structures are stabilized by twofold intermolecular hydrogen bonding between the carboxylic acid head groups. Moreover, in-situ dilution of liquid mixtures induced phase transitions of the monolayer structures, accompanied by an alteration of the size and shape of cavity voids in the 2-dimensional molecular assembly.