Contact: Contact: International Center for Materials Nanoarchitectonics (MANAMANA), Nakata (ex. 8806)), Nakata (ex. 8806)

Venue: Seminar Room #431, MANA Bldg., NamikiDate: Time:

Supra-Molecular Self Assembly at Surfaces: Rational Architectures for Addressable Molecular Switches

Dr. Thomas A. JungHead, Molecular Nanoscience Laboratory for Micro- and

Nanotechnology, Paul Scherrer InstituteOne 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. By combining concepts of supra-molecular chemistry and surface science, increasingly complex functional layers have been manufactured and explored. Selective chemical bonding, conformational bi-stability, and 2D phase behaviour produce distinctly different functional layers. Binary molecular systems which involve longer range dipole forces and entropic mobility provide the basis for an increased periodicity. In conjunction with a conformational mechanism the spacing between individual supramolecular units has very recently been increased to 7.2 nm. Beyond supra-molecular assembly, extended networks have been created by a thermally activated chemical reaction and have been used as a template for supra-molecular organisation of ad molecules. A single chain covalent polymer has also been formed. ‘Random walk’ analysis reveals conclusive statements on the host-guest interaction of pores. Ultimately, the assembly of adressable supra-molecular rotor-stator systems and their Arrhenius type activation of libration is described which tops in the demonstration of a locally actuated supra-molecular rotational switch. Most recently, the successful assembly of extended molecular layers on insulator thin films has been demonstrated. All these examples have in common that the supra-molecular structures are extremely well defined on a level which is impossible to reach by conventional top-down assembly techniques.

15:30-16:3015:30-16:30Dec 15th MondayDec 15th Monday