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1

Phase transitions in confined lamellar phases

Ciach A.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2007

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Vol. 55, nr 2

179-186

EN

Effects of confinement on mechanical, structural and thermodynamic properties of uniform fluids are very well understood. In contrast, a general theory based on statistical thermodynamics for confined nonuniform and non-isotropic phases, such as the lamellar phase, is in its infancy. In this review we focus on the lamellar phase confined in a slit or in a pipe in order to illustrate various effects of confinement. We limit ourselves to the results obtained by M. Tasinkevych, V. Babin and the author for lamellar phases in oil-water-surfactant mixtures within a generic semi-microscopic model, using a mean-field approximation. We show that compared to isotropic fluids the excess grand potential contains additional terms associated with structural deformations. These terms depend on the type of the confining walls, the shape of the container and on the thickness of the lamella. As a result of the dependence of the structure of the confined lamellar phase on the shape of the container, capillary lamellarization and capillary delamellarization is found in slits and in pipes respectively.

2

Solvation Forces in Near-Critical Fluids. Ising Model Results

Maciołek A., Ciach A.

Polish Journal of Chemistry

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2001

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Vol. 75, nr 4

481-500

EN

Recent developments in the statistical theory of simple fluids in a film geometry near bulk criticality is reviewed.We summarize results obtained by exact or approximate, but very accurate methods within Ising model. Particular attention is paid to the properties of the measurable solvation force and its relation to the structure of the confined system, in the Ising model given by magnetization profiles. Relevance of the reviewed results for various physical systems is briefly discussed.

3

Self-Assembling Systems in Restricted Geometry

Ciach A., Tasinkevych M.

Polish Journal of Chemistry

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2001

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Vol. 75, nr 1

1-28

EN

Results obtained within Ciach-Hoye-Stell model of oil-water-surfactant mixtures in restricted geometry are reviewed. Special attention is paid to ordering effects of a surface (or two parallel surfaces) close to phase boundaries between lamellar and microemulsion or water-rich phases. Relations between the structure of the confined self-assembling system and the measurable quantities are discussed. Predictions of the Ciach-Hoye-Stell model are compared with Landau-Ginzburg and membrane theories and with experimental results.