Biomedical subjects

M Heni

Publications and source records attributed to M Heni.

3 recordsLinked to original sources

PubMed2002

Triple-point wetting on rough substrates.

The influence of substrate roughness on the wetting scenario of adsorbed van der Waals films is investigated by theory and experiment. Calculating the bending free energy penalty of a solid sheet picking up the substrate roughness, we show that a finite roughness always leads to triple-point wetting reducing the widths of the adsorbed solid films considerably as compared to that of smooth substrates. Testing the theory against our experimental data for molecular hydrogen adsorbed on gold, we find quantitative agreement.

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PubMed2000

Surface freezing on patterned substrates

We show that the structure of a substrate pattern drastically influences the nature of surface freezing. By using phenomenological theory and computer simulations of a hard sphere fluid next to a substrate formed by a periodic array of fixed spheres, we find that a pattern which is commensurate with the bulk crystal induces complete surface freezing through a cascade of layering transitions. A rhombic pattern, on the other hand, either generates a crystalline sheet which is unstable as a bulk phase or prohibits surface freezing completely.

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PubMed1999

Interfacial free energy of hard-sphere fluids and solids near a hard wall.

A hard-sphere system near a planar structureless hard wall is considered in thermodynamic equilibrium. The associated interfacial free energies are calculated both for a bulk fluid and a bulk face-centered-cubic crystal along (111), (110), and (100) orientation. Combining Monte Carlo simulations and thermodynamic integration, we obtain the wall-fluid and the wall-solid interfacial free energy over the whole range of possible bulk densities. The "exact" computer simulation data are compared to theoretical approximations. For moderate bulk densities, the wall-fluid interfacial free energies compare reasonably well with scaled-particle theory and density functional results. For the wall-crystal interface, we propose a simple analytical cell theory which yields good agreement with our simulation data over the whole range of bulk crystal densities.

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