The associating lattice gas in the presence of interacting solutes.
We have investigated the phase diagram of a statistical model for hydrogen-bonding solutions for polar solutes. The structured solvent is represented by an associating lattice gas, which presents anomalous density and liquid-liquid coexistence. Polar solute particles and solvent particles interact attractively, while the solvent-solvent interaction is made directional through bonding arms, which mimic hydrogen bonds. The model behavior is obtained via Monte Carlo simulations in the grand-canonical ensemble, for different sets of parameters. For small solute chemical potential and weak attraction between solute and solvent particles, addition of solute yields a shift in the transition lines of the pure solvent. This is the scenario explored by different authors, in the pursuit of stabilizing the water liquid-liquid coexistence line. However, as we show, in the case of larger solute chemical potentials, or of stronger solute-solvent attractions, new phases may arise.
Universidade Federal de Santa Catarina, Rua Pedro João Pereira, 150 - Mato Alto, 88900-000 Araranguá SC, Brazil.
Mauricio
M
Girardi
Universidade Federal de Santa Catarina, Rua Pedro João Pereira, 150 - Mato Alto, 88900-000 Araranguá SC, Brazil.
Marcia M
MM
Szortyka
Instituto de Física, Universidade de São Paulo, Caixa Postal 66318, 05315-970 São Paulo, SP, Brazil.
Vera B
VB
Henriques
Instituto de Física, Universidade Federal do Rio Grande do Sul - Caixa Postal 15051, CEP 91501-970 Porto Alegre, Rio Grande do Sul, Brazil.
Marcia C
MC
Barbosa