Dresden 2006 – wissenschaftliches Programm
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CPP: Chemische Physik und Polymerphysik
CPP 27: POSTER Polymer Physics and Materials
CPP 27.5: Poster
Donnerstag, 30. März 2006, 17:00–19:00, P2
Phase properties of confined dipolar fluids — •Matthias Gramzow1 and PD Dr. Sabine H. L. Klapp1,2 — 1Stranski Laboratorium für Physikalische und Theoretische Chemie, Technische Universität Berlin, Strasse des 17.Juni 135, 10623 Berlin — 2TU Berlin, Institut für Theoretische Physik, Hardenbergstrasse 36, 10623 Berlin
The phase behavior and structural properties of various dipolar model fluids confined to a slit pore are investigated using density functional theory in meanfield (MF) and truncated modified meanfield (MMF) approximation. As a first step we approximate the inhomogeneous number density in the pore as a constant and consider only the orientational structure. Our focus lies on the description of isotropic and anisotropic fluid phases.
In the MF calculations we find first- and second-order isotropic-to-ferroelectric as well as isotropic liquid-to-gas phase transitions. For both types of phase transitions the confinement shifts the critical points towards lower temperatures. It also shifts the chemical potential, where the direction of the shift depends on the model considered. Moreover, in very narrow pores the isotropic liquid-to-gas phase transition is entirely suppressed.
Finally, we compare our MF results for the phase behavior to those from the more sophisticated MMF approach. The latter also provides information on the local orientational structure which turns out to be anisotropic even in globally isotropic phases.