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E Enciso

Publications and source records attributed to E Enciso.

14 recordsLinked to original sources

Characterization of latex particle arrays by gas adsorption.

Assemblies of colloidal particles are frequently used in novel applications, and this requires nondestructive methods allowing overall characterization of the sample and collection of information about the quality of the arrays. From suspensions of polystyrene, poly[styrene-co-(2-hydroxyethylmethacrylate)], poly[styrene-co-acrylic acid], and poly[styrene-co-methacrylic acid], assemblies of spherical particles were obtained by elimination of the solvent in different ways-evaporation, gravity deposition, and filtration. These latex particle packings were characterized by scanning and transmission electron microscopy and by gas adsorption to determine the efficiency of packing. The surface area, total pore volume, and pore size distributions obtained from the adsorption and desorption data were related to characteristic parameters calculated for cubic close-packed spherical particles.

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Unconventional density dependence of the stochastic dynamics in an organic liquid.

The density dependence of the diffusive rotational and center-of-mass dynamics of 2-methyl-pyridine is investigated by means of the concurrent use of quasielastic neutron scattering and molecular dynamics simulations. The dependence of both translation and rotational diffusion coefficients shows a distinctive change of slope with increasing density taking place about rho=0.975 g/cm3. Such a change in the dynamics can be related to observations made in other liquids composed of oblate-spheroidal particles.

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Critical behavior of ionic solids.

Phase transitions of lattice models of ionic crystals are studied by computer simulation. The nature of order-disorder transitions on different crystal structures is established and compared with the behavior of related Ising models. It is found that for both, continuous and first order transitions the basic features seem to be similar to those of Ising systems.

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Reentrant miscibility in fluids with spherical interactions.

We have obtained the closed-loop fluid-fluid immiscibility in the phase diagram of a binary mixture with interactions with spherical symmetry. That topology appears when a short-range attractive interaction is considered between unlike pair molecules. We present "exact" results obtained from Monte Carlo simulation on different ensembles and results from the application of a first-order perturbation theory.

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Molecular approach to the interpretation of the dielectric relaxation spectrum of a molecular glass former

The frequency-dependent dielectric function of ethanol at temperatures within the normal liquid range is evaluated by means of computer molecular dynamics simulations and compared with recent experimental data. The calculated spectra show a similar structure to those reported from experimental measurements and the temperature dependence of its most prominent bands also follows the experimental estimates. An attempt is also made to assign the most intense bands to specific molecular reorientations.

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