Im Rahmen des physikalischen Kolloquiums spricht am
Dienstag, den 24. April 2012 um 17:00 Uhr im Hans-Geiger-Hörsaal

Prof. Dr. Peter Beton (School of Physics and Astronomy - Nottingham)

über das Thema:

"Order and Disorder in Two-dimensional Molecular Templates"

The role of disorder in the formation of two-dimensional networks is currently attracting great interest and recent results on a supramolecular network which is stabilized by entropy and formed at a solid/liquid interface will be presented. These networks map directly onto a rhombus tiling of the plane and support a random tiling phase which has been studied widely by theorists over several decades but only recently realised experimentally. The networks are analyzed by treating them as projections of the (111) surface of a simple cubic crystal. The order within the arrays can then be characterized by from the height correlations of this virtual surface. It is also shown that topological defects are supported within this array. The choice of solvent is shown to be very important in the statistical properties of such arrays and phase transitions to ordered phases occur when the interaction between molecular tiles includes an asymmetric contribution which is comparable with the thermal energy kBT2. Growth of the networks, which are dynamically-arrested systems will also be consider. The trapping of guest species such as coronene and C60 in the random molecular rhombus network is also discussed. The presence of C60 leads to the growth of a second supramolecular layer stabilized by the guest molecule. This growth can be reversed through the introduction of coronene which displace the fullerene guest3. The role of disorder in the formation of covalently bound molecular networks will also be presented.