### Abstract

Using Monte Carlo simulation, we study the influence of geometric confinement on demixing for a series of symmetric non-additive hard spheres mixtures confined in slit pores. We consider both a wide range of positive non-additivities and a series of pore widths, ranging from the pure two dimensional limit to a large pore width where results are close to the bulk three dimensional case. Critical parameters are extracted by means of finite size analysis. As a general trend, we find that for this particular case in which demixing is induced by volume effects, the critical demixing densities (and pressures) increase due to confinement between neutral walls, following the expected behavior for phase equilibria of systems confined by pure repulsive walls: i.e., confinement generally enhances miscibility. However, a non-monotonous dependence of the critical pressure and density with pore size is found for small non-additivities. In this latter case, it turns out that an otherwise stable bulk mixture can be unexpectedly forced to demix by simple geometric confinement when the pore width decreases down to approximately one and a half molecular diameters.

Original language | English (US) |
---|---|

Article number | 014702 |

Journal | Journal of Chemical Physics |

Volume | 142 |

Issue number | 1 |

DOIs | |

State | Published - Jan 7 2015 |

Externally published | Yes |

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### ASJC Scopus subject areas

- Physics and Astronomy(all)
- Physical and Theoretical Chemistry

### Cite this

*Journal of Chemical Physics*,

*142*(1), [014702]. https://doi.org/10.1063/1.4905273

**Demixing and confinement of non-additive hard-sphere mixtures in slit pores.** / Almarza, N. G.; Martín, C.; Lomba, E.; Quijano, Cecilia.

Research output: Contribution to journal › Article

*Journal of Chemical Physics*, vol. 142, no. 1, 014702. https://doi.org/10.1063/1.4905273

}

TY - JOUR

T1 - Demixing and confinement of non-additive hard-sphere mixtures in slit pores

AU - Almarza, N. G.

AU - Martín, C.

AU - Lomba, E.

AU - Quijano, Cecilia

PY - 2015/1/7

Y1 - 2015/1/7

N2 - Using Monte Carlo simulation, we study the influence of geometric confinement on demixing for a series of symmetric non-additive hard spheres mixtures confined in slit pores. We consider both a wide range of positive non-additivities and a series of pore widths, ranging from the pure two dimensional limit to a large pore width where results are close to the bulk three dimensional case. Critical parameters are extracted by means of finite size analysis. As a general trend, we find that for this particular case in which demixing is induced by volume effects, the critical demixing densities (and pressures) increase due to confinement between neutral walls, following the expected behavior for phase equilibria of systems confined by pure repulsive walls: i.e., confinement generally enhances miscibility. However, a non-monotonous dependence of the critical pressure and density with pore size is found for small non-additivities. In this latter case, it turns out that an otherwise stable bulk mixture can be unexpectedly forced to demix by simple geometric confinement when the pore width decreases down to approximately one and a half molecular diameters.

AB - Using Monte Carlo simulation, we study the influence of geometric confinement on demixing for a series of symmetric non-additive hard spheres mixtures confined in slit pores. We consider both a wide range of positive non-additivities and a series of pore widths, ranging from the pure two dimensional limit to a large pore width where results are close to the bulk three dimensional case. Critical parameters are extracted by means of finite size analysis. As a general trend, we find that for this particular case in which demixing is induced by volume effects, the critical demixing densities (and pressures) increase due to confinement between neutral walls, following the expected behavior for phase equilibria of systems confined by pure repulsive walls: i.e., confinement generally enhances miscibility. However, a non-monotonous dependence of the critical pressure and density with pore size is found for small non-additivities. In this latter case, it turns out that an otherwise stable bulk mixture can be unexpectedly forced to demix by simple geometric confinement when the pore width decreases down to approximately one and a half molecular diameters.

UR - http://www.scopus.com/inward/record.url?scp=84923802738&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84923802738&partnerID=8YFLogxK

U2 - 10.1063/1.4905273

DO - 10.1063/1.4905273

M3 - Article

VL - 142

JO - Journal of Chemical Physics

JF - Journal of Chemical Physics

SN - 0021-9606

IS - 1

M1 - 014702

ER -