Dresden 2003 – scientific programme

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DY: Dynamik und Statistische Physik

DY 37: Critical phenomena and phase transitions II

DY 37.2: Talk

Wednesday, March 26, 2003, 16:45–17:00, G\"OR/229

Phase behavior of confined dipolar fluids — •Sabine Klapp — Stranski-Laboratorium für Physikalische und Theoretische Chemie, Sekr. TC7, Technische Universität Berlin, Strasse des 17. Juni 124, 10623 Berlin

Fluids confined to nanoporous materials can exhibit a phase behavior strongly different from what is observed in the bulk. In the present contribution we consider confined, anisotropic model fluids interacting via long–range, direction–dependent dipolar interactions, focussing on the possibility of global orientational order. Two types of confinement are discussed and compared: (i) a fluid squeezed in a single slit–shaped pore as it occurs in well–characterized carbons (or the surface force apparatus), and ii) a fluid adsorbed to a highly disordered porous medium, e.g., dilute silica aerogel. Results are obtained with Monte–Carlo simulations (model (i)) and replica–hypernetted chain integral equations (model (ii)). Despite the different physical situations considered (simple versus complex pore geometry), we find for both models the tendency of the confined fluid to develop long–range orientational order to be strongly enhanced (1,2); the origins for this behavior, however, turn out to be quite different.

1) S. H. L. Klapp and M. Schoen, J. Chem. Phys. 117, 8050 (2002).
2) C. Spöler and S. H. L. Klapp, J. Chem. Phys., to appear in 2003.