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Paola Gallo |
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Università di Roma Tre |
Abstract
Modifications
of dynamical and thermodynamical behavior of liquids in confinement are
of the uttermost importance. Many liquids are confined in systems of interest
for both technological applications and biology. Very few computer simulations
on the study of the glass transition scenario in confined liquids are available.
We present an extensive study upon cooling on the behavior of a model glass
former, a liquid Lennard Jones binary mixture, confined in a model for
xerogels. Modification of the dynamical and thermodynamical behavior on
approaching the glass transition with respect to the bulk are studied in
detail. In particular a test of the Mode Coupling predictions is performed
with respect to the bulk behavior and upon varying the host confining medium
characteristics. A study of the thermodynamic behavior via inherent structure
analysis is also performed. The Mode Copuling Theory appears to be able
to account for the behaviour of the liquid mixture also in confinement,
but with important modification of the parameters of the theory with respect
to the bulk. The mode coupling crossover temperature and the Kauzman temperature
are evaluated. Both appear to occur at lower temperatures with respect
to the bulk. The possible effect of confinement on dynamical heterogeneities
is also discussed for this model.The results can help to shed light on
the influence of this important feature on the glass transition.