Theoretische und experimentelle Untersuchungen von Benetzungseigenschaften von dünnen ein- und zweikomponentigen Polymerfilmen

• Applicant: Professor Dr. Kurt Binder (†)
• Subject Area: Theoretical Condensed Matter Physics
• Term: from 1998 to 2004
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 5102386

This project aims at the development of theoretical models for thin polymeric films adsorbed on solid substrate, and intends to characterize the wetting properties of these films with the help of Monte Carlo simulations and accompanying analytical methods (in particular the self-consistent field theory of macromolecules). Polymer chains are modeled by coarse-grained beadspring models with variable chain stiffness (via a bond angle potential). Chain length, temperatur and bulk density, film thickness, and the strength of the substrate potential are treated as variable parameters. Both short range and long range substrate monomer interactions are considered, as well as combinations therof. Determining the individual surface tensions substrate polymer gSP, substrate-vacuum gSV and polymer-vacuum gPV the wetting transitions shall be located and it shall be studied how the contact angle depends on the system parameters. Particular interest is devoted to the correlation between the thermodynamic states of the polymer film and the polymer configurations at the interfaces (orientation and/or deformation of the coils, enrichment of chain ends, changes of the local density, etc.) and corresponding entropic contributions.In a second step a generalization to two-component systems (symmetrical binary polymer mixtures AB) is planned to clarify the conditions under which phase separation occurs in perpendicular orientation to the substrate or horizontally. In the latter case we are particularly interested in the interaction of the interface polymer A - polymer B with the interface between the polymerfilm and the vacuum. In the first case we are particularly interested in the roughening of the polymer film caused by lateral unmixing.For both problems we plan to make connections both with fundamental theory (as it is available for Ising model and simple fluids) and with corresponding experiments. Finally the generalization of our studies to laterally structured substrates will be considered.

• DFG Programme: Priority Programmes
• Subproject of: SPP 1052: Benetzung und Strukturbildung an Grenzflächen
• Participating Persons: Professor Dr. Marcus Müller; Professor Dr. Peter Müller-Buschbaum