Dear Colleagues
Tomorrow Wednesday, at 17:15, the Kolloquium series of SS05 will start
with the talk outlined below.
From 16:45, there will be tea and coffee in front of the lecture hall
16 G 05 at the Irchel Campus of the University
(the usual place!). For directions or further information, go to
http://www.physik.unizh.ch/teaching/kolloquium05/kolloquium.html
You will notice that there are still two slots of the Kolloquium
program open: May 18 and June 29. Suggestions for speakers
are welcome.
With best regards,
Juerg Osterwalder
Molecular and Supra-Molecular Self Assembly: Condensed Matter Physics
Projected into 2 Dimensions
Thomas Jung
Laboratory for Micro- and Nanotechnology, Paul Scherrer Institute,
Villigen
One of the key challenges in molecular machines and devices is the
reproducible assembly of functional units in an addressable way e.g. in
2D arrays at surfaces. Using a variety of different molecules with
specifically designed structure, increasingly complex functional layers
have been manufactured and explored. Selective molecular interaction is
the generic origin of molecular self assembly [1] and a variety of
different mechanisms have been identified: Selective chemical bonding
[2], conformational bi-stability [3], and 2D phase behaviour [4]
produce distinctly different functional layers. Binary molecular
systems which involve longer range dipole forces and entropic mobility
provide the basis for an increased periodicity [5]. In conjunction with
a conformational mechanism the spacing between individual
supramolecular units has very recently been increased to 7.2 nm [6].
Going beyond supra-molecular assembly extended networks have been
created by a thermally activated chemical reaction [7] and have been
used as a template for supra-molecular organisation of ad-C60
molecules. Most recently the first successful assembly of extended
molecular layers on insulator thin films has been demonstrated [8]. All
these examples have in common that the supra-molecular structures are
extremely well defined and identical on a level which is impossible to
reach by convential top-down assembly techniques. Following the
discussion of the physics and chemistry involved in the formation of
these versatile structures I shall review and update the concept of
mechanic and electronic ‘function’ on a single molecular scale.
[1] G. M. Whitesides, J. P. Mathias and C. T. Seto. Science 254, 1312
(1991)
[2] S. Berner et. al. Chem. Phys. Lett. 348, 175 (2001)
[3] T. A. Jung et al. Nature 386, 696 (1997)
[4] S. Berner et. al. Phys. Rev. B 68, 115410 (2003), Additional
Manuscript in Preparation
[5] M. de Wild et al. ChemPhysChem 10 881 (2002)
[6] D. Bonifazi et al. Angewandte Chemie Intl. Ed., 43, 4759 – 4763
(2004).
[7] M. Stoehr et al. Manuscript in Preparation
[8] L. Ramoino et al. Manuscript in Preparation
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Prof. Dr. Jürg Osterwalder
Physik-Institut, Universität Zürich
Winterthurerstr. 190
CH-8057 Zürich, Switzerland
phone: +41 44 635 5827 <<< NOTE NEW AREA CODE ! >>>
lab: +41 44 635 5745
sekr: +41 44 635 5781
fax: +41 44 635 5704
e-mail: osterwal(a)physik.unizh.ch
web: http://www.physik.unizh.ch/groups/grouposterwalder/
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