ABSTRACT
The Maxwell construction together with molecular dynamics simulation is used to study the gas-liquid phase coexistence of quasi-two-dimensional Stockmayer fluids. The phase coexistence curves and corresponding critical points under different dipole strength are obtained, and the critical properties are calculated. We investigate the dependence of the critical point and critical properties on the dipole strength. When the dipole strength is increased, the abrupt disappearance of the gas-liquid phase coexistence in quasi-two-dimensional Stockmayer fluids is not found. However, if the dipole strength is large enough, it does lead to the formation of very long reversible chains which makes the relaxation of the system very slow and the observation of phase coexistence rather difficult or even impossible.
Subject(s)
Gases/chemistry , Molecular Dynamics SimulationABSTRACT
Using Monte Carlo simulation, we investigate the structural phase behavior of a continuum molecular model for self-assembling semiflexible equilibrium polymers in two dimensions. Particle-particle interaction is modeled via a Lennard-Jones potential with tunable anisotropic attraction. Depending on the strength of the anisotropy, we find the formation of reversible networks as well as stiff rodlike aggregates. The phase transition observed in the presence of the network structures is compared to predictions of the Tlusty-Safran defect model.
ABSTRACT
The partial phase behavior of a continuum molecular model for self-assembling semiflexible equilibrium polymers is studied via Monte Carlo and molecular dynamics simulation. We investigate the transfer from ordinary gas-liquid coexistence to the appearance of liquid crystallinity driven by excluded volume interaction between rodlike aggregates. The transfer between the two types of phase behavior is governed by a tunable anisotropic attractive interaction between monomer particles. The relation to dipolar fluid models, which are also known to form reversible chains, is discussed.
