A three-dimensional vector lattice model for a mixture of water, oil and amphiphile is considered on the simple cubic lattice. For a balanced system with equal water and oil concentrations the ground state exhibits, when the surfactant is strong, an ordered bicontinuous structure in addition to pure oil/water and pure surfactant states. The model is transformed, integrating out exactly the surfactant orientational degrees of freedom, in an effective spin-1 model with two-, three, five-and seven-body interactions with temperature dependent interaction strengths. This effective model is then investigated using the local mean-field approximation. The phase diagram of the model is derived and discussed, with particular attention to the structured ordered phase. In the disordered phase a microemulsion region is also found.
Structured phases of a three-dimensional vector lattice model for oil-water-surfactant mixtures / C. Buzano; L. R. Evangelista; A. Pelizzola. - In: MOLECULAR CRYSTALS AND LIQUID CRYSTALS SCIENCE AND TECHNOLOGY. SECTION A, MOLECULAR CRYSTALS AND LIQUID CRYSTALS. - ISSN 1058-725X. - 290(1996), pp. 41-48. ((Intervento presentato al convegno 2nd Italian-Liquid-Crystal-Society(SICL) Meeting tenutosi a Ravenna nel May 30-Jun 01, 1996.
Titolo: | Structured phases of a three-dimensional vector lattice model for oil-water-surfactant mixtures |
Autori: | |
Data di pubblicazione: | 1996 |
Rivista: | |
Abstract: | A three-dimensional vector lattice model for a mixture of water, oil and amphiphile is considered... on the simple cubic lattice. For a balanced system with equal water and oil concentrations the ground state exhibits, when the surfactant is strong, an ordered bicontinuous structure in addition to pure oil/water and pure surfactant states. The model is transformed, integrating out exactly the surfactant orientational degrees of freedom, in an effective spin-1 model with two-, three, five-and seven-body interactions with temperature dependent interaction strengths. This effective model is then investigated using the local mean-field approximation. The phase diagram of the model is derived and discussed, with particular attention to the structured ordered phase. In the disordered phase a microemulsion region is also found. |
Appare nelle tipologie: | 4.1 Contributo in Atti di convegno |
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