[Zurück]

B. Hartl, G. Kahl, K. Cui, S. De Feyter, M. Walter, S. Mertens:
"Predictive theoretical modeling of molecular self-assembly at an electrochemical solid-liquid interface";
Poster: 10th Liquid Matter Conference (2017), Lubljana, Slowenien; 17.07.2017 - 21.07.2017; in: "Liquids 2017 10TH LIQUID MATTER CONFERENCE", (2017), S. 7.007.

In recent experiments [1] the spontaneous and reversible transition between two- and three-dimensional self-assembly scenarios of a supramolecular system (PQPClO4) at a solid-liquid interface under electrochemical conditions [Au(111) in 0.1 M HClO4] has been shown. By a simple variation of the interfacial potential, it was possible to
selectively organize the target molecules in an open porous pattern, to fill these pores to form an auto-host-guest structure or to stack the building blocks in a stratified bilayer.
In complementary theoretical investigations effort was dedicated to rationalize these experimental observations. To this end the molecules were modeled either as simple steric entities, endowed with multipolar moments, which reflect the actual charge distributions of the individual atoms that build up the molecule; alternatively, ab initio
based interactions were included to complement the steric interparticle interactions.
The self-assembly scenarios of these molecular models at the solid-liquid interface were studied and identified via optimization tools that are based on evolutionary algorithms. The complexity of the problem forces us to use advanced ideas of these optimization tools. Specifically, we employ a basin hopping based memetic search approach which combines heuristics, making use of already obtained knowledge, and deterministic local search strategies. The evolutionary operations as well as the local search strategies are optimized for the self-assembly problem such that the most favorable solutions in configuration space can be explored efficiently, gradually approaching the global optimum.
Our theoretical results allow to predict, on the basis of the underlying molecular model, the experimental conditions under which the various self-assembly scenarios can be observed. In addition, indications about the location of the ClO4- anion relative to the cation can be given, an information which is not accessible experimentally.

[1] K. Cui, K.S. Mali, O. Ivasenko, D. Wu, X. Feng, M. Walter, K. Müllen, S. De Feyter, and S.F.L. Mertens, Angew. Chem. Int. Ed. 53, 12951 (2014).

molecular self-assembly solid-liquid interface soft matter physics evolutionary algorithms

http://publik.tuwien.ac.at/files/publik_265111.pdf

Projektleitung Gerhard Kahl:
DFS